Merge "Add --skip-config flag to soong_ui.bash"
diff --git a/android/arch.go b/android/arch.go
index 1fbba19..340f136 100644
--- a/android/arch.go
+++ b/android/arch.go
@@ -1572,20 +1572,20 @@
 // with Neon will break those users.
 func getNdkAbisConfig() []archConfig {
 	return []archConfig{
-		{"arm", "armv7-a", "", []string{"armeabi-v7a"}},
 		{"arm64", "armv8-a-branchprot", "", []string{"arm64-v8a"}},
-		{"x86", "", "", []string{"x86"}},
+		{"arm", "armv7-a", "", []string{"armeabi-v7a"}},
 		{"x86_64", "", "", []string{"x86_64"}},
+		{"x86", "", "", []string{"x86"}},
 	}
 }
 
 // getAmlAbisConfig returns a list of archConfigs for the ABIs supported by mainline modules.
 func getAmlAbisConfig() []archConfig {
 	return []archConfig{
-		{"arm", "armv7-a-neon", "", []string{"armeabi-v7a"}},
 		{"arm64", "armv8-a", "", []string{"arm64-v8a"}},
-		{"x86", "", "", []string{"x86"}},
+		{"arm", "armv7-a-neon", "", []string{"armeabi-v7a"}},
 		{"x86_64", "", "", []string{"x86_64"}},
+		{"x86", "", "", []string{"x86"}},
 	}
 }
 
diff --git a/android/deapexer.go b/android/deapexer.go
index 63508d7..de3f635 100644
--- a/android/deapexer.go
+++ b/android/deapexer.go
@@ -15,49 +15,75 @@
 package android
 
 import (
-	"fmt"
-	"strings"
-
 	"github.com/google/blueprint"
 )
 
 // Provides support for interacting with the `deapexer` module to which a `prebuilt_apex` module
 // will delegate the work to export files from a prebuilt '.apex` file.
+//
+// The actual processing that is done is quite convoluted but it is all about combining information
+// from multiple different sources in order to allow a prebuilt module to use a file extracted from
+// an apex file. As follows:
+//
+// 1. A prebuilt module, e.g. prebuilt_bootclasspath_fragment or java_import needs to use a file
+//    from a prebuilt_apex/apex_set. It knows the path of the file within the apex but does not know
+//    where the apex file is or what apex to use.
+//
+// 2. The connection between the prebuilt module and the prebuilt_apex/apex_set is created through
+//    use of an exported_... property on the latter. That causes four things to occur:
+//    a. A `deapexer` mopdule is created by the prebuilt_apex/apex_set to extract files from the
+//       apex file.
+//    b. A dependency is added from the prebuilt_apex/apex_set modules onto the prebuilt modules
+//       listed in those properties.
+//    c. An APEX variant is created for each of those prebuilt modules.
+//    d. A dependency is added from the prebuilt modules to the `deapexer` module.
+//
+// 3. The prebuilt_apex/apex_set modules do not know which files are available in the apex file.
+//    That information could be specified on the prebuilt_apex/apex_set modules but without
+//    automated generation of those modules it would be expensive to maintain. So, instead they
+//    obtain that information from the prebuilt modules. They do not know what files are actually in
+//    the apex file either but they know what files they need from it. So, the
+//    prebuilt_apex/apex_set modules obtain the files that should be in the apex file from those
+//    modules and then pass those onto the `deapexer` module.
+//
+// 4. The `deapexer` module's ninja rule extracts all the files from the apex file into an output
+//    directory and checks that all the expected files are there. The expected files are declared as
+//    the outputs of the ninja rule so they are available to other modules.
+//
+// 5. The prebuilt modules then retrieve the paths to the files that they needed from the `deapexer`
+//    module.
+//
+// The files that are passed to `deapexer` and those that are passed back have a unique identifier
+// that links them together. e.g. If the `deapexer` is passed something like this:
+//     javalib/core-libart.jar -> javalib/core-libart.jar
+// it will return something like this:
+//     javalib/core-libart.jar -> out/soong/.....deapexer.../javalib/core-libart.jar
+//
+// The reason why the `deapexer` module is separate from the prebuilt_apex/apex_set is to avoid
+// cycles. e.g.
+//   prebuilt_apex "com.android.art" depends upon java_import "core-libart":
+//       This is so it can create an APEX variant of the latter and obtain information about the
+//       files that it needs from the apex file.
+//   java_import "core-libart" depends upon `deapexer` module:
+//       This is so it can retrieve the paths to the files it needs.
 
 // The information exported by the `deapexer` module, access it using `DeapxerInfoProvider`.
 type DeapexerInfo struct {
 	// map from the name of an exported file from a prebuilt_apex to the path to that file. The
-	// exported file name is of the form <module>{<tag>} where <tag> is currently only allowed to be
-	// ".dexjar".
+	// exported file name is the apex relative path, e.g. javalib/core-libart.jar.
 	//
 	// See Prebuilt.ApexInfoMutator for more information.
 	exports map[string]Path
 }
 
-// The set of supported prebuilt export tags. Used to verify the tag parameter for
-// `PrebuiltExportPath`.
-var supportedPrebuiltExportTags = map[string]struct{}{
-	".dexjar": {},
-}
-
 // PrebuiltExportPath provides the path, or nil if not available, of a file exported from the
 // prebuilt_apex that created this ApexInfo.
 //
-// The exported file is identified by the module name and the tag:
-// * The module name is the name of the module that contributed the file when the .apex file
-//   referenced by the prebuilt_apex was built. It must be specified in one of the exported_...
-//   properties on the prebuilt_apex module.
-// * The tag identifies the type of file and is dependent on the module type.
+// The exported file is identified by the apex relative path, e.g. "javalib/core-libart.jar".
 //
 // See apex/deapexer.go for more information.
-func (i DeapexerInfo) PrebuiltExportPath(name, tag string) Path {
-
-	if _, ok := supportedPrebuiltExportTags[tag]; !ok {
-		panic(fmt.Errorf("unsupported prebuilt export tag %q, expected one of %s",
-			tag, strings.Join(SortedStringKeys(supportedPrebuiltExportTags), ", ")))
-	}
-
-	path := i.exports[name+"{"+tag+"}"]
+func (i DeapexerInfo) PrebuiltExportPath(apexRelativePath string) Path {
+	path := i.exports[apexRelativePath]
 	return path
 }
 
@@ -79,5 +105,31 @@
 	blueprint.BaseDependencyTag
 }
 
+// Mark this tag so dependencies that use it are excluded from APEX contents.
+func (t deapexerTagStruct) ExcludeFromApexContents() {}
+
+var _ ExcludeFromApexContentsTag = DeapexerTag
+
 // A tag that is used for dependencies on the `deapexer` module.
 var DeapexerTag = deapexerTagStruct{}
+
+// RequiredFilesFromPrebuiltApex must be implemented by modules that require files to be exported
+// from a prebuilt_apex/apex_set.
+type RequiredFilesFromPrebuiltApex interface {
+	// RequiredFilesFromPrebuiltApex returns a list of the file paths (relative to the root of the
+	// APEX's contents) that the implementing module requires from within a prebuilt .apex file.
+	//
+	// For each file path this will cause the file to be extracted out of the prebuilt .apex file, and
+	// the path to the extracted file will be stored in the DeapexerInfo using the APEX relative file
+	// path as the key, The path can then be retrieved using the PrebuiltExportPath(key) method.
+	RequiredFilesFromPrebuiltApex(ctx BaseModuleContext) []string
+}
+
+// Marker interface that identifies dependencies on modules that may require files from a prebuilt
+// apex.
+type RequiresFilesFromPrebuiltApexTag interface {
+	blueprint.DependencyTag
+
+	// Method that differentiates this interface from others.
+	RequiresFilesFromPrebuiltApex()
+}
diff --git a/android/neverallow.go b/android/neverallow.go
index 41b399a..19b58a7 100644
--- a/android/neverallow.go
+++ b/android/neverallow.go
@@ -55,6 +55,7 @@
 	AddNeverAllowRules(createCcSdkVariantRules()...)
 	AddNeverAllowRules(createUncompressDexRules()...)
 	AddNeverAllowRules(createMakefileGoalRules()...)
+	AddNeverAllowRules(createInitFirstStageRules()...)
 }
 
 // Add a NeverAllow rule to the set of rules to apply.
@@ -216,6 +217,15 @@
 	}
 }
 
+func createInitFirstStageRules() []Rule {
+	return []Rule{
+		NeverAllow().
+			Without("name", "init_first_stage").
+			With("install_in_root", "true").
+			Because("install_in_root is only for init_first_stage."),
+	}
+}
+
 func neverallowMutator(ctx BottomUpMutatorContext) {
 	m, ok := ctx.Module().(Module)
 	if !ok {
diff --git a/apex/Android.bp b/apex/Android.bp
index 14c8771..6269757 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -31,6 +31,7 @@
     testSrcs: [
         "apex_test.go",
         "bootclasspath_fragment_test.go",
+        "classpath_element_test.go",
         "platform_bootclasspath_test.go",
         "systemserver_classpath_fragment_test.go",
         "vndk_test.go",
diff --git a/apex/apex.go b/apex/apex.go
index 9e714ab..7ffa6cc 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -171,8 +171,7 @@
 	Ignore_system_library_special_case *bool
 
 	// Whenever apex_payload.img of the APEX should include dm-verity hashtree.
-	// Default value is false.
-	// TODO(b/190621617): change default value to true.
+	// Default value is true.
 	Generate_hashtree *bool
 
 	// Whenever apex_payload.img of the APEX should not be dm-verity signed. Should be only
@@ -415,6 +414,9 @@
 	// Path of API coverage generate file
 	apisUsedByModuleFile   android.ModuleOutPath
 	apisBackedByModuleFile android.ModuleOutPath
+
+	// Collect the module directory for IDE info in java/jdeps.go.
+	modulePaths []string
 }
 
 // apexFileClass represents a type of file that can be included in APEX.
@@ -1343,7 +1345,7 @@
 
 // See the generate_hashtree property
 func (a *apexBundle) shouldGenerateHashtree() bool {
-	return proptools.BoolDefault(a.properties.Generate_hashtree, false)
+	return proptools.BoolDefault(a.properties.Generate_hashtree, true)
 }
 
 // See the test_only_unsigned_payload property
@@ -1690,6 +1692,9 @@
 
 	handleSpecialLibs := !android.Bool(a.properties.Ignore_system_library_special_case)
 
+	// Collect the module directory for IDE info in java/jdeps.go.
+	a.modulePaths = append(a.modulePaths, ctx.ModuleDir())
+
 	// TODO(jiyong): do this using WalkPayloadDeps
 	// TODO(jiyong): make this clean!!!
 	ctx.WalkDepsBlueprint(func(child, parent blueprint.Module) bool {
@@ -1756,7 +1761,9 @@
 						ctx.PropertyErrorf("systemserverclasspath_fragments", "%q is not a systemserverclasspath_fragment module", depName)
 						return false
 					}
-					filesInfo = append(filesInfo, apexClasspathFragmentProtoFile(ctx, child))
+					if af := apexClasspathFragmentProtoFile(ctx, child); af != nil {
+						filesInfo = append(filesInfo, *af)
+					}
 					return true
 				}
 			case javaLibTag:
@@ -2159,17 +2166,23 @@
 	}
 
 	// Add classpaths.proto config.
-	filesToAdd = append(filesToAdd, apexClasspathFragmentProtoFile(ctx, module))
+	if af := apexClasspathFragmentProtoFile(ctx, module); af != nil {
+		filesToAdd = append(filesToAdd, *af)
+	}
 
 	return filesToAdd
 }
 
-// apexClasspathFragmentProtoFile returns apexFile structure defining the classpath.proto config that
-// the module contributes to the apex.
-func apexClasspathFragmentProtoFile(ctx android.ModuleContext, module blueprint.Module) apexFile {
-	fragmentInfo := ctx.OtherModuleProvider(module, java.ClasspathFragmentProtoContentInfoProvider).(java.ClasspathFragmentProtoContentInfo)
-	classpathProtoOutput := fragmentInfo.ClasspathFragmentProtoOutput
-	return newApexFile(ctx, classpathProtoOutput, classpathProtoOutput.Base(), fragmentInfo.ClasspathFragmentProtoInstallDir.Rel(), etc, nil)
+// apexClasspathFragmentProtoFile returns *apexFile structure defining the classpath.proto config that
+// the module contributes to the apex; or nil if the proto config was not generated.
+func apexClasspathFragmentProtoFile(ctx android.ModuleContext, module blueprint.Module) *apexFile {
+	info := ctx.OtherModuleProvider(module, java.ClasspathFragmentProtoContentInfoProvider).(java.ClasspathFragmentProtoContentInfo)
+	if !info.ClasspathFragmentProtoGenerated {
+		return nil
+	}
+	classpathProtoOutput := info.ClasspathFragmentProtoOutput
+	af := newApexFile(ctx, classpathProtoOutput, classpathProtoOutput.Base(), info.ClasspathFragmentProtoInstallDir.Rel(), etc, nil)
+	return &af
 }
 
 // apexFileForBootclasspathFragmentContentModule creates an apexFile for a bootclasspath_fragment
@@ -2355,16 +2368,30 @@
 	})
 }
 
-// Enforce that Java deps of the apex are using stable SDKs to compile
+// checkUpdatable enforces APEX and its transitive dep properties to have desired values for updatable APEXes.
 func (a *apexBundle) checkUpdatable(ctx android.ModuleContext) {
 	if a.Updatable() {
 		if String(a.properties.Min_sdk_version) == "" {
 			ctx.PropertyErrorf("updatable", "updatable APEXes should set min_sdk_version as well")
 		}
 		a.checkJavaStableSdkVersion(ctx)
+		a.checkClasspathFragments(ctx)
 	}
 }
 
+// checkClasspathFragments enforces that all classpath fragments in deps generate classpaths.proto config.
+func (a *apexBundle) checkClasspathFragments(ctx android.ModuleContext) {
+	ctx.VisitDirectDeps(func(module android.Module) {
+		if tag := ctx.OtherModuleDependencyTag(module); tag == bcpfTag || tag == sscpfTag {
+			info := ctx.OtherModuleProvider(module, java.ClasspathFragmentProtoContentInfoProvider).(java.ClasspathFragmentProtoContentInfo)
+			if !info.ClasspathFragmentProtoGenerated {
+				ctx.OtherModuleErrorf(module, "is included in updatable apex %v, it must not set generate_classpaths_proto to false", ctx.ModuleName())
+			}
+		}
+	})
+}
+
+// checkJavaStableSdkVersion enforces that all Java deps are using stable SDKs to compile.
 func (a *apexBundle) checkJavaStableSdkVersion(ctx android.ModuleContext) {
 	// Visit direct deps only. As long as we guarantee top-level deps are using stable SDKs,
 	// java's checkLinkType guarantees correct usage for transitive deps
@@ -2383,7 +2410,7 @@
 	})
 }
 
-// Ensures that the all the dependencies are marked as available for this APEX
+// checkApexAvailability ensures that the all the dependencies are marked as available for this APEX.
 func (a *apexBundle) checkApexAvailability(ctx android.ModuleContext) {
 	// Let's be practical. Availability for test, host, and the VNDK apex isn't important
 	if ctx.Host() || a.testApex || a.vndkApex {
@@ -2435,6 +2462,14 @@
 	})
 }
 
+// Collect information for opening IDE project files in java/jdeps.go.
+func (a *apexBundle) IDEInfo(dpInfo *android.IdeInfo) {
+	dpInfo.Deps = append(dpInfo.Deps, a.properties.Java_libs...)
+	dpInfo.Deps = append(dpInfo.Deps, a.properties.Bootclasspath_fragments...)
+	dpInfo.Deps = append(dpInfo.Deps, a.properties.Systemserverclasspath_fragments...)
+	dpInfo.Paths = append(dpInfo.Paths, a.modulePaths...)
+}
+
 var (
 	apexAvailBaseline        = makeApexAvailableBaseline()
 	inverseApexAvailBaseline = invertApexBaseline(apexAvailBaseline)
diff --git a/apex/apex_test.go b/apex/apex_test.go
index 8b97467..983b820 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -4643,7 +4643,12 @@
 		t.Helper()
 		platformBootclasspath := ctx.ModuleForTests("platform-bootclasspath", "android_common")
 		indexRule := platformBootclasspath.Rule("monolithic_hidden_API_index")
-		java.CheckHiddenAPIRuleInputs(t, expectedInputs, indexRule)
+		java.CheckHiddenAPIRuleInputs(t, "index", expectedInputs, indexRule)
+	}
+
+	fragment := java.ApexVariantReference{
+		Apex:   proptools.StringPtr("myapex"),
+		Module: proptools.StringPtr("my-bootclasspath-fragment"),
 	}
 
 	t.Run("prebuilt only", func(t *testing.T) {
@@ -4658,7 +4663,13 @@
 					src: "myapex-arm.apex",
 				},
 			},
-			exported_java_libs: ["libfoo", "libbar"],
+			exported_bootclasspath_fragments: ["my-bootclasspath-fragment"],
+		}
+
+		prebuilt_bootclasspath_fragment {
+			name: "my-bootclasspath-fragment",
+			contents: ["libfoo", "libbar"],
+			apex_available: ["myapex"],
 		}
 
 		java_import {
@@ -4673,18 +4684,19 @@
 				jars: ["libbar.jar"],
 			},
 			apex_available: ["myapex"],
+			shared_library: false,
 		}
 	`
 
-		ctx := testDexpreoptWithApexes(t, bp, "", preparer)
+		ctx := testDexpreoptWithApexes(t, bp, "", preparer, fragment)
 		checkBootDexJarPath(t, ctx, "libfoo", "out/soong/.intermediates/myapex.deapexer/android_common/deapexer/javalib/libfoo.jar")
 		checkBootDexJarPath(t, ctx, "libbar", "out/soong/.intermediates/myapex.deapexer/android_common/deapexer/javalib/libbar.jar")
 
 		// Verify the correct module jars contribute to the hiddenapi index file.
 		checkHiddenAPIIndexInputs(t, ctx, `
-.intermediates/libbar.stubs/android_common/combined/libbar.stubs.jar
-.intermediates/libfoo/android_common_myapex/combined/libfoo.jar
-`)
+			out/soong/.intermediates/libbar.stubs/android_common/combined/libbar.stubs.jar
+			out/soong/.intermediates/libfoo/android_common_myapex/combined/libfoo.jar
+		`)
 	})
 
 	t.Run("apex_set only", func(t *testing.T) {
@@ -4692,7 +4704,13 @@
 		apex_set {
 			name: "myapex",
 			set: "myapex.apks",
-			exported_java_libs: ["libfoo", "libbar"],
+			exported_bootclasspath_fragments: ["my-bootclasspath-fragment"],
+		}
+
+		prebuilt_bootclasspath_fragment {
+			name: "my-bootclasspath-fragment",
+			contents: ["libfoo", "libbar"],
+			apex_available: ["myapex"],
 		}
 
 		java_import {
@@ -4707,18 +4725,19 @@
 				jars: ["libbar.jar"],
 			},
 			apex_available: ["myapex"],
+			shared_library: false,
 		}
 	`
 
-		ctx := testDexpreoptWithApexes(t, bp, "", preparer)
+		ctx := testDexpreoptWithApexes(t, bp, "", preparer, fragment)
 		checkBootDexJarPath(t, ctx, "libfoo", "out/soong/.intermediates/myapex.deapexer/android_common/deapexer/javalib/libfoo.jar")
 		checkBootDexJarPath(t, ctx, "libbar", "out/soong/.intermediates/myapex.deapexer/android_common/deapexer/javalib/libbar.jar")
 
 		// Verify the correct module jars contribute to the hiddenapi index file.
 		checkHiddenAPIIndexInputs(t, ctx, `
-.intermediates/libbar.stubs/android_common/combined/libbar.stubs.jar
-.intermediates/libfoo/android_common_myapex/combined/libfoo.jar
-`)
+			out/soong/.intermediates/libbar.stubs/android_common/combined/libbar.stubs.jar
+			out/soong/.intermediates/libfoo/android_common_myapex/combined/libfoo.jar
+		`)
 	})
 
 	t.Run("prebuilt with source library preferred", func(t *testing.T) {
@@ -4733,7 +4752,13 @@
 					src: "myapex-arm.apex",
 				},
 			},
-			exported_java_libs: ["libfoo", "libbar"],
+			exported_bootclasspath_fragments: ["my-bootclasspath-fragment"],
+		}
+
+		prebuilt_bootclasspath_fragment {
+			name: "my-bootclasspath-fragment",
+			contents: ["libfoo", "libbar"],
+			apex_available: ["myapex"],
 		}
 
 		java_import {
@@ -4754,6 +4779,7 @@
 				jars: ["libbar.jar"],
 			},
 			apex_available: ["myapex"],
+			shared_library: false,
 		}
 
 		java_sdk_library {
@@ -4769,7 +4795,7 @@
 		// prebuilt_apex module always depends on the prebuilt, and so it doesn't
 		// find the dex boot jar in it. We either need to disable the source libfoo
 		// or make the prebuilt libfoo preferred.
-		testDexpreoptWithApexes(t, bp, "module libfoo does not provide a dex boot jar", preparer)
+		testDexpreoptWithApexes(t, bp, "module libfoo does not provide a dex boot jar", preparer, fragment)
 	})
 
 	t.Run("prebuilt library preferred with source", func(t *testing.T) {
@@ -4784,7 +4810,13 @@
 					src: "myapex-arm.apex",
 				},
 			},
-			exported_java_libs: ["libfoo", "libbar"],
+			exported_bootclasspath_fragments: ["my-bootclasspath-fragment"],
+		}
+
+		prebuilt_bootclasspath_fragment {
+			name: "my-bootclasspath-fragment",
+			contents: ["libfoo", "libbar"],
+			apex_available: ["myapex"],
 		}
 
 		java_import {
@@ -4807,6 +4839,7 @@
 				jars: ["libbar.jar"],
 			},
 			apex_available: ["myapex"],
+			shared_library: false,
 		}
 
 		java_sdk_library {
@@ -4817,15 +4850,15 @@
 		}
 	`
 
-		ctx := testDexpreoptWithApexes(t, bp, "", preparer)
+		ctx := testDexpreoptWithApexes(t, bp, "", preparer, fragment)
 		checkBootDexJarPath(t, ctx, "libfoo", "out/soong/.intermediates/myapex.deapexer/android_common/deapexer/javalib/libfoo.jar")
 		checkBootDexJarPath(t, ctx, "libbar", "out/soong/.intermediates/myapex.deapexer/android_common/deapexer/javalib/libbar.jar")
 
 		// Verify the correct module jars contribute to the hiddenapi index file.
 		checkHiddenAPIIndexInputs(t, ctx, `
-.intermediates/prebuilt_libbar.stubs/android_common/combined/libbar.stubs.jar
-.intermediates/prebuilt_libfoo/android_common_myapex/combined/libfoo.jar
-`)
+			out/soong/.intermediates/prebuilt_libbar.stubs/android_common/combined/libbar.stubs.jar
+			out/soong/.intermediates/prebuilt_libfoo/android_common_myapex/combined/libfoo.jar
+		`)
 	})
 
 	t.Run("prebuilt with source apex preferred", func(t *testing.T) {
@@ -4853,7 +4886,13 @@
 					src: "myapex-arm.apex",
 				},
 			},
-			exported_java_libs: ["libfoo", "libbar"],
+			exported_bootclasspath_fragments: ["my-bootclasspath-fragment"],
+		}
+
+		prebuilt_bootclasspath_fragment {
+			name: "my-bootclasspath-fragment",
+			contents: ["libfoo", "libbar"],
+			apex_available: ["myapex"],
 		}
 
 		java_import {
@@ -4874,6 +4913,7 @@
 				jars: ["libbar.jar"],
 			},
 			apex_available: ["myapex"],
+			shared_library: false,
 		}
 
 		java_sdk_library {
@@ -4884,15 +4924,15 @@
 		}
 	`
 
-		ctx := testDexpreoptWithApexes(t, bp, "", preparer)
+		ctx := testDexpreoptWithApexes(t, bp, "", preparer, fragment)
 		checkBootDexJarPath(t, ctx, "libfoo", "out/soong/.intermediates/libfoo/android_common_apex10000/hiddenapi/libfoo.jar")
 		checkBootDexJarPath(t, ctx, "libbar", "out/soong/.intermediates/libbar/android_common_myapex/hiddenapi/libbar.jar")
 
 		// Verify the correct module jars contribute to the hiddenapi index file.
 		checkHiddenAPIIndexInputs(t, ctx, `
-.intermediates/libbar/android_common_myapex/javac/libbar.jar
-.intermediates/libfoo/android_common_apex10000/javac/libfoo.jar
-`)
+			out/soong/.intermediates/libbar/android_common_myapex/javac/libbar.jar
+			out/soong/.intermediates/libfoo/android_common_apex10000/javac/libfoo.jar
+		`)
 	})
 
 	t.Run("prebuilt preferred with source apex disabled", func(t *testing.T) {
@@ -4920,7 +4960,13 @@
 					src: "myapex-arm.apex",
 				},
 			},
-			exported_java_libs: ["libfoo", "libbar"],
+			exported_bootclasspath_fragments: ["my-bootclasspath-fragment"],
+		}
+
+		prebuilt_bootclasspath_fragment {
+			name: "my-bootclasspath-fragment",
+			contents: ["libfoo", "libbar"],
+			apex_available: ["myapex"],
 		}
 
 		java_import {
@@ -4943,6 +4989,7 @@
 				jars: ["libbar.jar"],
 			},
 			apex_available: ["myapex"],
+			shared_library: false,
 		}
 
 		java_sdk_library {
@@ -4953,15 +5000,15 @@
 		}
 	`
 
-		ctx := testDexpreoptWithApexes(t, bp, "", preparer)
+		ctx := testDexpreoptWithApexes(t, bp, "", preparer, fragment)
 		checkBootDexJarPath(t, ctx, "libfoo", "out/soong/.intermediates/myapex.deapexer/android_common/deapexer/javalib/libfoo.jar")
 		checkBootDexJarPath(t, ctx, "libbar", "out/soong/.intermediates/myapex.deapexer/android_common/deapexer/javalib/libbar.jar")
 
 		// Verify the correct module jars contribute to the hiddenapi index file.
 		checkHiddenAPIIndexInputs(t, ctx, `
-.intermediates/prebuilt_libbar.stubs/android_common/combined/libbar.stubs.jar
-.intermediates/prebuilt_libfoo/android_common_myapex/combined/libfoo.jar
-`)
+			out/soong/.intermediates/prebuilt_libbar.stubs/android_common/combined/libbar.stubs.jar
+			out/soong/.intermediates/prebuilt_libfoo/android_common_myapex/combined/libfoo.jar
+		`)
 	})
 }
 
@@ -6528,7 +6575,7 @@
 	android.AssertStringEquals(t, "myapex input", extractorOutput, copiedApex.Input.String())
 }
 
-func testNoUpdatableJarsInBootImage(t *testing.T, errmsg string, preparer android.FixturePreparer) {
+func testNoUpdatableJarsInBootImage(t *testing.T, errmsg string, preparer android.FixturePreparer, fragments ...java.ApexVariantReference) {
 	t.Helper()
 
 	bp := `
@@ -6547,6 +6594,15 @@
 			apex_available: [
 				"some-non-updatable-apex",
 			],
+			compile_dex: true,
+		}
+
+		bootclasspath_fragment {
+			name: "some-non-updatable-fragment",
+			contents: ["some-non-updatable-apex-lib"],
+			apex_available: [
+				"some-non-updatable-apex",
+			],
 		}
 
 		java_library {
@@ -6578,7 +6634,7 @@
 		apex {
 			name: "some-non-updatable-apex",
 			key: "some-non-updatable-apex.key",
-			java_libs: ["some-non-updatable-apex-lib"],
+			bootclasspath_fragments: ["some-non-updatable-fragment"],
 			updatable: false,
 		}
 
@@ -6593,7 +6649,7 @@
 		apex {
 			name: "com.android.art.debug",
 			key: "com.android.art.debug.key",
-			java_libs: ["some-art-lib"],
+			bootclasspath_fragments: ["art-bootclasspath-fragment"],
 			updatable: true,
 			min_sdk_version: "current",
 		}
@@ -6626,10 +6682,10 @@
 		}
 	`
 
-	testDexpreoptWithApexes(t, bp, errmsg, preparer)
+	testDexpreoptWithApexes(t, bp, errmsg, preparer, fragments...)
 }
 
-func testDexpreoptWithApexes(t *testing.T, bp, errmsg string, preparer android.FixturePreparer) *android.TestContext {
+func testDexpreoptWithApexes(t *testing.T, bp, errmsg string, preparer android.FixturePreparer, fragments ...java.ApexVariantReference) *android.TestContext {
 	t.Helper()
 
 	fs := android.MockFS{
@@ -6657,11 +6713,22 @@
 		PrepareForTestWithApexBuildComponents,
 		preparer,
 		fs.AddToFixture(),
-		android.FixtureAddTextFile("frameworks/base/boot/Android.bp", `
-			platform_bootclasspath {
-				name: "platform-bootclasspath",
+		android.FixtureModifyMockFS(func(fs android.MockFS) {
+			if _, ok := fs["frameworks/base/boot/Android.bp"]; !ok {
+				insert := ""
+				for _, fragment := range fragments {
+					insert += fmt.Sprintf("{apex: %q, module: %q},\n", *fragment.Apex, *fragment.Module)
+				}
+				fs["frameworks/base/boot/Android.bp"] = []byte(fmt.Sprintf(`
+					platform_bootclasspath {
+						name: "platform-bootclasspath",
+						fragments: [
+  						%s
+						],
+					}
+				`, insert))
 			}
-		`),
+		}),
 	).
 		ExtendWithErrorHandler(errorHandler).
 		RunTestWithBp(t, bp)
@@ -6700,6 +6767,47 @@
 	`)
 }
 
+func TestUpdatable_should_not_set_generate_classpaths_proto(t *testing.T) {
+	testApexError(t, `"mysystemserverclasspathfragment" .* it must not set generate_classpaths_proto to false`, `
+		apex {
+			name: "myapex",
+			key: "myapex.key",
+			systemserverclasspath_fragments: [
+				"mysystemserverclasspathfragment",
+			],
+			min_sdk_version: "29",
+			updatable: true,
+		}
+
+		apex_key {
+			name: "myapex.key",
+			public_key: "testkey.avbpubkey",
+			private_key: "testkey.pem",
+		}
+
+		java_library {
+			name: "foo",
+			srcs: ["b.java"],
+			min_sdk_version: "29",
+			installable: true,
+			apex_available: [
+				"myapex",
+			],
+		}
+
+		systemserverclasspath_fragment {
+			name: "mysystemserverclasspathfragment",
+			generate_classpaths_proto: false,
+			contents: [
+				"foo",
+			],
+			apex_available: [
+				"myapex",
+			],
+		}
+	`)
+}
+
 func TestNoUpdatableJarsInBootImage(t *testing.T) {
 	// Set the BootJars in dexpreopt.GlobalConfig and productVariables to the same value. This can
 	// result in an invalid configuration as it does not set the ArtApexJars and allows art apex
@@ -6728,7 +6836,11 @@
 
 	t.Run("updatable jar from ART apex in the ART boot image => ok", func(t *testing.T) {
 		preparer := java.FixtureConfigureBootJars("com.android.art.debug:some-art-lib")
-		testNoUpdatableJarsInBootImage(t, "", preparer)
+		fragment := java.ApexVariantReference{
+			Apex:   proptools.StringPtr("com.android.art.debug"),
+			Module: proptools.StringPtr("art-bootclasspath-fragment"),
+		}
+		testNoUpdatableJarsInBootImage(t, "", preparer, fragment)
 	})
 
 	t.Run("updatable jar from ART apex in the framework boot image => error", func(t *testing.T) {
@@ -6760,7 +6872,11 @@
 
 	t.Run("non-updatable jar from some other apex in the framework boot image => ok", func(t *testing.T) {
 		preparer := java.FixtureConfigureBootJars("some-non-updatable-apex:some-non-updatable-apex-lib")
-		testNoUpdatableJarsInBootImage(t, "", preparer)
+		fragment := java.ApexVariantReference{
+			Apex:   proptools.StringPtr("some-non-updatable-apex"),
+			Module: proptools.StringPtr("some-non-updatable-fragment"),
+		}
+		testNoUpdatableJarsInBootImage(t, "", preparer, fragment)
 	})
 
 	t.Run("nonexistent jar in the ART boot image => error", func(t *testing.T) {
@@ -6791,6 +6907,11 @@
 func TestDexpreoptAccessDexFilesFromPrebuiltApex(t *testing.T) {
 	preparer := java.FixtureConfigureBootJars("myapex:libfoo")
 	t.Run("prebuilt no source", func(t *testing.T) {
+		fragment := java.ApexVariantReference{
+			Apex:   proptools.StringPtr("myapex"),
+			Module: proptools.StringPtr("my-bootclasspath-fragment"),
+		}
+
 		testDexpreoptWithApexes(t, `
 			prebuilt_apex {
 				name: "myapex" ,
@@ -6802,36 +6923,21 @@
 						src: "myapex-arm.apex",
 					},
 				},
-			exported_java_libs: ["libfoo"],
-		}
+				exported_bootclasspath_fragments: ["my-bootclasspath-fragment"],
+			}
 
-		java_import {
-			name: "libfoo",
-			jars: ["libfoo.jar"],
-		}
-`, "", preparer)
-	})
+			prebuilt_bootclasspath_fragment {
+				name: "my-bootclasspath-fragment",
+				contents: ["libfoo"],
+				apex_available: ["myapex"],
+			}
 
-	t.Run("prebuilt no source", func(t *testing.T) {
-		testDexpreoptWithApexes(t, `
-			prebuilt_apex {
-				name: "myapex" ,
-				arch: {
-					arm64: {
-						src: "myapex-arm64.apex",
-					},
-					arm: {
-						src: "myapex-arm.apex",
-					},
-				},
-			exported_java_libs: ["libfoo"],
-		}
-
-		java_import {
-			name: "libfoo",
-			jars: ["libfoo.jar"],
-		}
-`, "", preparer)
+			java_import {
+				name: "libfoo",
+				jars: ["libfoo.jar"],
+				apex_available: ["myapex"],
+			}
+		`, "", preparer, fragment)
 	})
 }
 
diff --git a/apex/bootclasspath_fragment_test.go b/apex/bootclasspath_fragment_test.go
index 1971dcd..66bc9e0 100644
--- a/apex/bootclasspath_fragment_test.go
+++ b/apex/bootclasspath_fragment_test.go
@@ -16,6 +16,7 @@
 
 import (
 	"fmt"
+	"sort"
 	"strings"
 	"testing"
 
@@ -359,6 +360,19 @@
 
 	addPrebuilt := func(prefer bool, contents ...string) android.FixturePreparer {
 		text := fmt.Sprintf(`
+			prebuilt_apex {
+				name: "com.android.art",
+				arch: {
+					arm64: {
+						src: "com.android.art-arm64.apex",
+					},
+					arm: {
+						src: "com.android.art-arm.apex",
+					},
+				},
+				exported_bootclasspath_fragments: ["mybootclasspathfragment"],
+			}
+
 			prebuilt_bootclasspath_fragment {
 				name: "mybootclasspathfragment",
 				image_name: "art",
@@ -372,7 +386,47 @@
 		return android.FixtureAddTextFile("prebuilts/module_sdk/art/Android.bp", text)
 	}
 
-	t.Run("boot image files", func(t *testing.T) {
+	t.Run("boot image files from source", func(t *testing.T) {
+		result := android.GroupFixturePreparers(
+			commonPreparer,
+
+			// Configure some libraries in the art bootclasspath_fragment that match the source
+			// bootclasspath_fragment's contents property.
+			java.FixtureConfigureBootJars("com.android.art:foo", "com.android.art:bar"),
+			addSource("foo", "bar"),
+		).RunTest(t)
+
+		ensureExactContents(t, result.TestContext, "com.android.art", "android_common_com.android.art_image", []string{
+			"etc/classpaths/bootclasspath.pb",
+			"javalib/arm/boot.art",
+			"javalib/arm/boot.oat",
+			"javalib/arm/boot.vdex",
+			"javalib/arm/boot-bar.art",
+			"javalib/arm/boot-bar.oat",
+			"javalib/arm/boot-bar.vdex",
+			"javalib/arm64/boot.art",
+			"javalib/arm64/boot.oat",
+			"javalib/arm64/boot.vdex",
+			"javalib/arm64/boot-bar.art",
+			"javalib/arm64/boot-bar.oat",
+			"javalib/arm64/boot-bar.vdex",
+			"javalib/bar.jar",
+			"javalib/foo.jar",
+		})
+
+		java.CheckModuleDependencies(t, result.TestContext, "com.android.art", "android_common_com.android.art_image", []string{
+			`bar`,
+			`com.android.art.key`,
+			`mybootclasspathfragment`,
+		})
+
+		// Make sure that the source bootclasspath_fragment copies its dex files to the predefined
+		// locations for the art image.
+		module := result.ModuleForTests("mybootclasspathfragment", "android_common_apex10000")
+		checkCopiesToPredefinedLocationForArt(t, result.Config, module, "bar", "foo")
+	})
+
+	t.Run("boot image files with preferred prebuilt", func(t *testing.T) {
 		result := android.GroupFixturePreparers(
 			commonPreparer,
 
@@ -407,7 +461,13 @@
 			`bar`,
 			`com.android.art.key`,
 			`mybootclasspathfragment`,
+			`prebuilt_com.android.art`,
 		})
+
+		// Make sure that the prebuilt bootclasspath_fragment copies its dex files to the predefined
+		// locations for the art image.
+		module := result.ModuleForTests("prebuilt_mybootclasspathfragment", "android_common_com.android.art")
+		checkCopiesToPredefinedLocationForArt(t, result.Config, module, "bar", "foo")
 	})
 
 	t.Run("source with inconsistency between config and contents", func(t *testing.T) {
@@ -528,11 +588,37 @@
 		`prebuilt_mybootclasspathfragment`,
 	})
 
-	java.CheckModuleDependencies(t, result.TestContext, "mybootclasspathfragment", "android_common", []string{
+	java.CheckModuleDependencies(t, result.TestContext, "mybootclasspathfragment", "android_common_com.android.art", []string{
+		`com.android.art.deapexer`,
 		`dex2oatd`,
 		`prebuilt_bar`,
 		`prebuilt_foo`,
 	})
+
+	module := result.ModuleForTests("mybootclasspathfragment", "android_common_com.android.art")
+	checkCopiesToPredefinedLocationForArt(t, result.Config, module, "bar", "foo")
+}
+
+// checkCopiesToPredefinedLocationForArt checks that the supplied modules are copied to the
+// predefined locations of boot dex jars used as inputs for the ART boot image.
+func checkCopiesToPredefinedLocationForArt(t *testing.T, config android.Config, module android.TestingModule, modules ...string) {
+	t.Helper()
+	bootJarLocations := []string{}
+	for _, output := range module.AllOutputs() {
+		output = android.StringRelativeToTop(config, output)
+		if strings.HasPrefix(output, "out/soong/test_device/dex_artjars_input/") {
+			bootJarLocations = append(bootJarLocations, output)
+		}
+	}
+
+	sort.Strings(bootJarLocations)
+	expected := []string{}
+	for _, m := range modules {
+		expected = append(expected, fmt.Sprintf("out/soong/test_device/dex_artjars_input/%s.jar", m))
+	}
+	sort.Strings(expected)
+
+	android.AssertArrayString(t, "copies to predefined locations for art", expected, bootJarLocations)
 }
 
 func TestBootclasspathFragmentContentsNoName(t *testing.T) {
diff --git a/apex/classpath_element_test.go b/apex/classpath_element_test.go
new file mode 100644
index 0000000..0193127
--- /dev/null
+++ b/apex/classpath_element_test.go
@@ -0,0 +1,317 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package apex
+
+import (
+	"reflect"
+	"testing"
+
+	"android/soong/android"
+	"android/soong/java"
+	"github.com/google/blueprint"
+)
+
+// Contains tests for java.CreateClasspathElements logic from java/classpath_element.go that
+// requires apexes.
+
+// testClasspathElementContext is a ClasspathElementContext suitable for use in tests.
+type testClasspathElementContext struct {
+	testContext *android.TestContext
+	module      android.Module
+	errs        []error
+}
+
+func (t *testClasspathElementContext) OtherModuleHasProvider(module blueprint.Module, provider blueprint.ProviderKey) bool {
+	return t.testContext.ModuleHasProvider(module, provider)
+}
+
+func (t *testClasspathElementContext) OtherModuleProvider(module blueprint.Module, provider blueprint.ProviderKey) interface{} {
+	return t.testContext.ModuleProvider(module, provider)
+}
+
+func (t *testClasspathElementContext) ModuleErrorf(fmt string, args ...interface{}) {
+	t.errs = append(t.errs, t.testContext.ModuleErrorf(t.module, fmt, args...))
+}
+
+var _ java.ClasspathElementContext = (*testClasspathElementContext)(nil)
+
+func TestCreateClasspathElements(t *testing.T) {
+	preparer := android.GroupFixturePreparers(
+		prepareForTestWithPlatformBootclasspath,
+		prepareForTestWithArtApex,
+		prepareForTestWithMyapex,
+		// For otherapex.
+		android.FixtureMergeMockFs(android.MockFS{
+			"system/sepolicy/apex/otherapex-file_contexts": nil,
+		}),
+		java.PrepareForTestWithJavaSdkLibraryFiles,
+		java.FixtureWithLastReleaseApis("foo", "othersdklibrary"),
+		android.FixtureWithRootAndroidBp(`
+		apex {
+			name: "com.android.art",
+			key: "com.android.art.key",
+ 			bootclasspath_fragments: [
+				"art-bootclasspath-fragment",
+			],
+			java_libs: [
+				"othersdklibrary",
+			],
+			updatable: false,
+		}
+
+		apex_key {
+			name: "com.android.art.key",
+			public_key: "com.android.art.avbpubkey",
+			private_key: "com.android.art.pem",
+		}
+
+		bootclasspath_fragment {
+			name: "art-bootclasspath-fragment",
+			apex_available: [
+				"com.android.art",
+			],
+			contents: [
+				"baz",
+				"quuz",
+			],
+		}
+
+		java_library {
+			name: "baz",
+			apex_available: [
+				"com.android.art",
+			],
+			srcs: ["b.java"],
+			installable: true,
+		}
+
+		java_library {
+			name: "quuz",
+			apex_available: [
+				"com.android.art",
+			],
+			srcs: ["b.java"],
+			installable: true,
+		}
+
+		apex {
+			name: "myapex",
+			key: "myapex.key",
+ 			bootclasspath_fragments: [
+				"mybootclasspath-fragment",
+			],
+			java_libs: [
+				"othersdklibrary",
+			],
+			updatable: false,
+		}
+
+		apex_key {
+			name: "myapex.key",
+			public_key: "testkey.avbpubkey",
+			private_key: "testkey.pem",
+		}
+
+		bootclasspath_fragment {
+			name: "mybootclasspath-fragment",
+			apex_available: [
+				"myapex",
+			],
+			contents: [
+				"bar",
+			],
+		}
+
+		java_library {
+			name: "bar",
+			srcs: ["b.java"],
+			installable: true,
+			apex_available: ["myapex"],
+			permitted_packages: ["bar"],
+		}
+
+		java_sdk_library {
+			name: "foo",
+			srcs: ["b.java"],
+		}
+
+		java_sdk_library {
+			name: "othersdklibrary",
+			srcs: ["b.java"],
+			shared_library: false,
+			apex_available: [
+				"com.android.art",
+				"myapex",
+			],
+		}
+
+		bootclasspath_fragment {
+			name: "non-apex-fragment",
+			contents: ["othersdklibrary"],
+		}
+
+		apex {
+			name: "otherapex",
+			key: "otherapex.key",
+			java_libs: [
+				"otherapexlibrary",
+			],
+			updatable: false,
+		}
+
+		apex_key {
+			name: "otherapex.key",
+			public_key: "testkey.avbpubkey",
+			private_key: "testkey.pem",
+		}
+
+		java_library {
+			name: "otherapexlibrary",
+			srcs: ["b.java"],
+			installable: true,
+			apex_available: ["otherapex"],
+			permitted_packages: ["otherapexlibrary"],
+		}
+
+		platform_bootclasspath {
+			name: "myplatform-bootclasspath",
+
+			fragments: [
+				{
+					apex: "com.android.art",
+					module: "art-bootclasspath-fragment",
+				},
+			],
+		}
+	`),
+	)
+
+	result := preparer.RunTest(t)
+
+	artFragment := result.Module("art-bootclasspath-fragment", "android_common_apex10000")
+	artBaz := result.Module("baz", "android_common_apex10000")
+	artQuuz := result.Module("quuz", "android_common_apex10000")
+
+	myFragment := result.Module("mybootclasspath-fragment", "android_common_apex10000")
+	myBar := result.Module("bar", "android_common_apex10000")
+
+	nonApexFragment := result.Module("non-apex-fragment", "android_common")
+	other := result.Module("othersdklibrary", "android_common_apex10000")
+
+	otherApexLibrary := result.Module("otherapexlibrary", "android_common_apex10000")
+
+	platformFoo := result.Module("quuz", "android_common")
+
+	bootclasspath := result.Module("myplatform-bootclasspath", "android_common")
+
+	// Use a custom assertion method instead of AssertDeepEquals as the latter formats the output
+	// using %#v which results in meaningless output as ClasspathElements are pointers.
+	assertElementsEquals := func(t *testing.T, message string, expected, actual java.ClasspathElements) {
+		if !reflect.DeepEqual(expected, actual) {
+			t.Errorf("%s: expected:\n  %s\n got:\n  %s", message, expected, actual)
+		}
+	}
+
+	expectFragmentElement := func(module android.Module, contents ...android.Module) java.ClasspathElement {
+		return &java.ClasspathFragmentElement{module, contents}
+	}
+	expectLibraryElement := func(module android.Module) java.ClasspathElement {
+		return &java.ClasspathLibraryElement{module}
+	}
+
+	newCtx := func() *testClasspathElementContext {
+		return &testClasspathElementContext{testContext: result.TestContext, module: bootclasspath}
+	}
+
+	// Verify that CreateClasspathElements works when given valid input.
+	t.Run("art:baz, art:quuz, my:bar, foo", func(t *testing.T) {
+		ctx := newCtx()
+		elements := java.CreateClasspathElements(ctx, []android.Module{artBaz, artQuuz, myBar, platformFoo}, []android.Module{artFragment, myFragment})
+		expectedElements := java.ClasspathElements{
+			expectFragmentElement(artFragment, artBaz, artQuuz),
+			expectFragmentElement(myFragment, myBar),
+			expectLibraryElement(platformFoo),
+		}
+		assertElementsEquals(t, "elements", expectedElements, elements)
+	})
+
+	// Verify that CreateClasspathElements detects when a fragment does not have an associated apex.
+	t.Run("non apex fragment", func(t *testing.T) {
+		ctx := newCtx()
+		elements := java.CreateClasspathElements(ctx, []android.Module{}, []android.Module{nonApexFragment})
+		android.FailIfNoMatchingErrors(t, "fragment non-apex-fragment{.*} is not part of an apex", ctx.errs)
+		expectedElements := java.ClasspathElements{}
+		assertElementsEquals(t, "elements", expectedElements, elements)
+	})
+
+	// Verify that CreateClasspathElements detects when an apex has multiple fragments.
+	t.Run("multiple fragments for same apex", func(t *testing.T) {
+		ctx := newCtx()
+		elements := java.CreateClasspathElements(ctx, []android.Module{}, []android.Module{artFragment, artFragment})
+		android.FailIfNoMatchingErrors(t, "apex com.android.art has multiple fragments, art-bootclasspath-fragment{.*} and art-bootclasspath-fragment{.*}", ctx.errs)
+		expectedElements := java.ClasspathElements{}
+		assertElementsEquals(t, "elements", expectedElements, elements)
+	})
+
+	// Verify that CreateClasspathElements detects when a library is in multiple fragments.
+	t.Run("library from multiple fragments", func(t *testing.T) {
+		ctx := newCtx()
+		elements := java.CreateClasspathElements(ctx, []android.Module{other}, []android.Module{artFragment, myFragment})
+		android.FailIfNoMatchingErrors(t, "library othersdklibrary{.*} is in two separate fragments, art-bootclasspath-fragment{.*} and mybootclasspath-fragment{.*}", ctx.errs)
+		expectedElements := java.ClasspathElements{}
+		assertElementsEquals(t, "elements", expectedElements, elements)
+	})
+
+	// Verify that CreateClasspathElements detects when a fragment's contents are not contiguous and
+	// are separated by a library from another fragment.
+	t.Run("discontiguous separated by fragment", func(t *testing.T) {
+		ctx := newCtx()
+		elements := java.CreateClasspathElements(ctx, []android.Module{artBaz, myBar, artQuuz, platformFoo}, []android.Module{artFragment, myFragment})
+		expectedElements := java.ClasspathElements{
+			expectFragmentElement(artFragment, artBaz, artQuuz),
+			expectFragmentElement(myFragment, myBar),
+			expectLibraryElement(platformFoo),
+		}
+		assertElementsEquals(t, "elements", expectedElements, elements)
+		android.FailIfNoMatchingErrors(t, "libraries from the same fragment must be contiguous, however baz{.*} and quuz{os:android,arch:common,apex:apex10000} from fragment art-bootclasspath-fragment{.*} are separated by libraries from fragment mybootclasspath-fragment{.*} like bar{.*}", ctx.errs)
+	})
+
+	// Verify that CreateClasspathElements detects when a fragment's contents are not contiguous and
+	// are separated by a standalone library.
+	t.Run("discontiguous separated by library", func(t *testing.T) {
+		ctx := newCtx()
+		elements := java.CreateClasspathElements(ctx, []android.Module{artBaz, platformFoo, artQuuz, myBar}, []android.Module{artFragment, myFragment})
+		expectedElements := java.ClasspathElements{
+			expectFragmentElement(artFragment, artBaz, artQuuz),
+			expectLibraryElement(platformFoo),
+			expectFragmentElement(myFragment, myBar),
+		}
+		assertElementsEquals(t, "elements", expectedElements, elements)
+		android.FailIfNoMatchingErrors(t, "libraries from the same fragment must be contiguous, however baz{.*} and quuz{os:android,arch:common,apex:apex10000} from fragment art-bootclasspath-fragment{.*} are separated by library quuz{.*}", ctx.errs)
+	})
+
+	// Verify that CreateClasspathElements detects when there a library on the classpath that
+	// indicates it is from an apex the supplied fragments list does not contain a fragment for that
+	// apex.
+	t.Run("no fragment for apex", func(t *testing.T) {
+		ctx := newCtx()
+		elements := java.CreateClasspathElements(ctx, []android.Module{artBaz, otherApexLibrary}, []android.Module{artFragment})
+		expectedElements := java.ClasspathElements{
+			expectFragmentElement(artFragment, artBaz),
+		}
+		assertElementsEquals(t, "elements", expectedElements, elements)
+		android.FailIfNoMatchingErrors(t, `library otherapexlibrary{.*} is from apexes \[otherapex\] which have no corresponding fragment in \[art-bootclasspath-fragment{.*}\]`, ctx.errs)
+	})
+}
diff --git a/apex/deapexer.go b/apex/deapexer.go
index c7cdbfa..c70da15 100644
--- a/apex/deapexer.go
+++ b/apex/deapexer.go
@@ -40,16 +40,6 @@
 // This is intentionally not registered by name as it is not intended to be used from within an
 // `Android.bp` file.
 
-// DeapexerExportedFile defines the properties needed to expose a file from the deapexer module.
-type DeapexerExportedFile struct {
-	// The tag parameter which must be passed to android.OutputFileProducer OutputFiles(tag) method
-	// to retrieve the path to the unpacked file.
-	Tag string
-
-	// The path within the APEX that needs to be exported.
-	Path string `android:"path"`
-}
-
 // DeapexerProperties specifies the properties supported by the deapexer module.
 //
 // As these are never intended to be supplied in a .bp file they use a different naming convention
@@ -62,7 +52,9 @@
 	CommonModules []string
 
 	// List of files exported from the .apex file by this module
-	ExportedFiles []DeapexerExportedFile
+	//
+	// Each entry is a path from the apex root, e.g. javalib/core-libart.jar.
+	ExportedFiles []string
 }
 
 type SelectedApexProperties struct {
@@ -107,27 +99,23 @@
 
 	exports := make(map[string]android.Path)
 
-	// Create mappings from name+tag to all the required exported paths.
-	for _, e := range p.properties.ExportedFiles {
-		tag := e.Tag
-		path := e.Path
-
+	// Create mappings from apex relative path to the extracted file's path.
+	exportedPaths := make(android.Paths, 0, len(exports))
+	for _, path := range p.properties.ExportedFiles {
 		// Populate the exports that this makes available.
-		exports[tag] = deapexerOutput.Join(ctx, path)
+		extractedPath := deapexerOutput.Join(ctx, path)
+		exports[path] = extractedPath
+		exportedPaths = append(exportedPaths, extractedPath)
 	}
 
 	// If the prebuilt_apex exports any files then create a build rule that unpacks the apex using
 	// deapexer and verifies that all the required files were created. Also, make the mapping from
-	// name+tag to path available for other modules.
+	// apex relative path to extracted file path available for other modules.
 	if len(exports) > 0 {
 		// Make the information available for other modules.
 		ctx.SetProvider(android.DeapexerProvider, android.NewDeapexerInfo(exports))
 
 		// Create a sorted list of the files that this exports.
-		exportedPaths := make(android.Paths, 0, len(exports))
-		for _, p := range exports {
-			exportedPaths = append(exportedPaths, p)
-		}
 		exportedPaths = android.SortedUniquePaths(exportedPaths)
 
 		// The apex needs to export some files so create a ninja rule to unpack the apex and check that
diff --git a/apex/platform_bootclasspath_test.go b/apex/platform_bootclasspath_test.go
index 7297926..bd4a9d5 100644
--- a/apex/platform_bootclasspath_test.go
+++ b/apex/platform_bootclasspath_test.go
@@ -234,12 +234,18 @@
 		apex {
 			name: "myapex",
 			key: "myapex.key",
-			java_libs: [
-				"bar",
+			bootclasspath_fragments: [
+				"my-bootclasspath-fragment",
 			],
 			updatable: false,
 		}
 
+		bootclasspath_fragment {
+			name: "my-bootclasspath-fragment",
+			contents: ["bar"],
+			apex_available: ["myapex"],
+		}
+
 		apex_key {
 			name: "myapex.key",
 			public_key: "testkey.avbpubkey",
@@ -267,6 +273,10 @@
 					apex: "com.android.art",
 					module: "art-bootclasspath-fragment",
 				},
+				{
+					apex: "myapex",
+					module: "my-bootclasspath-fragment",
+				},
 			],
 		}
 `,
@@ -283,7 +293,8 @@
 	})
 
 	java.CheckPlatformBootclasspathFragments(t, result, "myplatform-bootclasspath", []string{
-		`com.android.art:art-bootclasspath-fragment`,
+		"com.android.art:art-bootclasspath-fragment",
+		"myapex:my-bootclasspath-fragment",
 	})
 
 	// Make sure that the myplatform-bootclasspath has the correct dependencies.
@@ -307,6 +318,7 @@
 
 		// The fragments.
 		`com.android.art:art-bootclasspath-fragment`,
+		`myapex:my-bootclasspath-fragment`,
 	})
 }
 
@@ -410,6 +422,12 @@
 
 		platform_bootclasspath {
 			name: "myplatform-bootclasspath",
+			fragments: [
+				{
+					apex: "myapex",
+					module:"mybootclasspath-fragment",
+				},
+			],
 		}
 `,
 	)
@@ -431,7 +449,7 @@
 		"platform:legacy.core.platform.api.stubs",
 
 		// Needed for generating the boot image.
-		`platform:dex2oatd`,
+		"platform:dex2oatd",
 
 		// The platform_bootclasspath intentionally adds dependencies on both source and prebuilt
 		// modules when available as it does not know which one will be preferred.
@@ -442,6 +460,9 @@
 
 		// Only a source module exists.
 		"myapex:bar",
+
+		// The fragments.
+		"myapex:mybootclasspath-fragment",
 	})
 }
 
diff --git a/apex/prebuilt.go b/apex/prebuilt.go
index 1283d23..ea06d45 100644
--- a/apex/prebuilt.go
+++ b/apex/prebuilt.go
@@ -17,7 +17,6 @@
 import (
 	"fmt"
 	"io"
-	"path/filepath"
 	"strconv"
 	"strings"
 
@@ -217,52 +216,57 @@
 	// apex specific variants of the exported java modules available for use from within make.
 	apexName := p.BaseModuleName()
 	for _, fi := range p.apexFilesForAndroidMk {
-		moduleName := fi.androidMkModuleName + "." + apexName
-		entries := android.AndroidMkEntries{
-			Class:        fi.class.nameInMake(),
-			OverrideName: moduleName,
-			OutputFile:   android.OptionalPathForPath(fi.builtFile),
-			Include:      "$(BUILD_SYSTEM)/soong_java_prebuilt.mk",
-			ExtraEntries: []android.AndroidMkExtraEntriesFunc{
-				func(ctx android.AndroidMkExtraEntriesContext, entries *android.AndroidMkEntries) {
-					entries.SetString("LOCAL_MODULE_PATH", p.installDir.ToMakePath().String())
-
-					// soong_java_prebuilt.mk sets LOCAL_MODULE_SUFFIX := .jar  Therefore
-					// we need to remove the suffix from LOCAL_MODULE_STEM, otherwise
-					// we will have foo.jar.jar
-					entries.SetString("LOCAL_MODULE_STEM", strings.TrimSuffix(fi.stem(), ".jar"))
-					var classesJar android.Path
-					var headerJar android.Path
-					if javaModule, ok := fi.module.(java.ApexDependency); ok {
-						classesJar = javaModule.ImplementationAndResourcesJars()[0]
-						headerJar = javaModule.HeaderJars()[0]
-					} else {
-						classesJar = fi.builtFile
-						headerJar = fi.builtFile
-					}
-					entries.SetString("LOCAL_SOONG_CLASSES_JAR", classesJar.String())
-					entries.SetString("LOCAL_SOONG_HEADER_JAR", headerJar.String())
-					entries.SetString("LOCAL_SOONG_DEX_JAR", fi.builtFile.String())
-					entries.SetString("LOCAL_DEX_PREOPT", "false")
-				},
-			},
-			ExtraFooters: []android.AndroidMkExtraFootersFunc{
-				func(w io.Writer, name, prefix, moduleDir string) {
-					// m <module_name> will build <module_name>.<apex_name> as well.
-					if fi.androidMkModuleName != moduleName {
-						fmt.Fprintf(w, ".PHONY: %s\n", fi.androidMkModuleName)
-						fmt.Fprintf(w, "%s: %s\n", fi.androidMkModuleName, moduleName)
-					}
-				},
-			},
-		}
-
+		entries := p.createEntriesForApexFile(fi, apexName)
 		entriesList = append(entriesList, entries)
 	}
 
 	return entriesList
 }
 
+// createEntriesForApexFile creates an AndroidMkEntries for the supplied apexFile
+func (p *prebuiltCommon) createEntriesForApexFile(fi apexFile, apexName string) android.AndroidMkEntries {
+	moduleName := fi.androidMkModuleName + "." + apexName
+	entries := android.AndroidMkEntries{
+		Class:        fi.class.nameInMake(),
+		OverrideName: moduleName,
+		OutputFile:   android.OptionalPathForPath(fi.builtFile),
+		Include:      "$(BUILD_SYSTEM)/soong_java_prebuilt.mk",
+		ExtraEntries: []android.AndroidMkExtraEntriesFunc{
+			func(ctx android.AndroidMkExtraEntriesContext, entries *android.AndroidMkEntries) {
+				entries.SetString("LOCAL_MODULE_PATH", p.installDir.ToMakePath().String())
+
+				// soong_java_prebuilt.mk sets LOCAL_MODULE_SUFFIX := .jar  Therefore
+				// we need to remove the suffix from LOCAL_MODULE_STEM, otherwise
+				// we will have foo.jar.jar
+				entries.SetString("LOCAL_MODULE_STEM", strings.TrimSuffix(fi.stem(), ".jar"))
+				var classesJar android.Path
+				var headerJar android.Path
+				if javaModule, ok := fi.module.(java.ApexDependency); ok {
+					classesJar = javaModule.ImplementationAndResourcesJars()[0]
+					headerJar = javaModule.HeaderJars()[0]
+				} else {
+					classesJar = fi.builtFile
+					headerJar = fi.builtFile
+				}
+				entries.SetString("LOCAL_SOONG_CLASSES_JAR", classesJar.String())
+				entries.SetString("LOCAL_SOONG_HEADER_JAR", headerJar.String())
+				entries.SetString("LOCAL_SOONG_DEX_JAR", fi.builtFile.String())
+				entries.SetString("LOCAL_DEX_PREOPT", "false")
+			},
+		},
+		ExtraFooters: []android.AndroidMkExtraFootersFunc{
+			func(w io.Writer, name, prefix, moduleDir string) {
+				// m <module_name> will build <module_name>.<apex_name> as well.
+				if fi.androidMkModuleName != moduleName {
+					fmt.Fprintf(w, ".PHONY: %s\n", fi.androidMkModuleName)
+					fmt.Fprintf(w, "%s: %s\n", fi.androidMkModuleName, moduleName)
+				}
+			},
+		},
+	}
+	return entries
+}
+
 // prebuiltApexModuleCreator defines the methods that need to be implemented by prebuilt_apex and
 // apex_set in order to create the modules needed to provide access to the prebuilt .apex file.
 type prebuiltApexModuleCreator interface {
@@ -549,21 +553,25 @@
 	}
 
 	// Compute the deapexer properties from the transitive dependencies of this module.
-	javaModules := []string{}
-	exportedFiles := map[string]string{}
+	commonModules := []string{}
+	exportedFiles := []string{}
 	ctx.WalkDeps(func(child, parent android.Module) bool {
 		tag := ctx.OtherModuleDependencyTag(child)
 
+		// If the child is not in the same apex as the parent then ignore it and all its children.
+		if !android.IsDepInSameApex(ctx, parent, child) {
+			return false
+		}
+
 		name := android.RemoveOptionalPrebuiltPrefix(ctx.OtherModuleName(child))
-		if java.IsBootclasspathFragmentContentDepTag(tag) || tag == exportedJavaLibTag {
-			javaModules = append(javaModules, name)
+		if _, ok := tag.(android.RequiresFilesFromPrebuiltApexTag); ok {
+			commonModules = append(commonModules, name)
 
-			// Add the dex implementation jar to the set of exported files. The path here must match the
-			// path of the file in the APEX created by apexFileForJavaModule(...).
-			exportedFiles[name+"{.dexjar}"] = filepath.Join("javalib", name+".jar")
+			requiredFiles := child.(android.RequiredFilesFromPrebuiltApex).RequiredFilesFromPrebuiltApex(ctx)
+			exportedFiles = append(exportedFiles, requiredFiles...)
 
-		} else if tag == exportedBootclasspathFragmentTag {
-			// Only visit the children of the bootclasspath_fragment for now.
+			// Visit the dependencies of this module just in case they also require files from the
+			// prebuilt apex.
 			return true
 		}
 
@@ -572,18 +580,13 @@
 
 	// Create properties for deapexer module.
 	deapexerProperties := &DeapexerProperties{
-		// Remove any duplicates from the java modules lists as a module may be included via a direct
+		// Remove any duplicates from the common modules lists as a module may be included via a direct
 		// dependency as well as transitive ones.
-		CommonModules: android.SortedUniqueStrings(javaModules),
+		CommonModules: android.SortedUniqueStrings(commonModules),
 	}
 
 	// Populate the exported files property in a fixed order.
-	for _, tag := range android.SortedStringKeys(exportedFiles) {
-		deapexerProperties.ExportedFiles = append(deapexerProperties.ExportedFiles, DeapexerExportedFile{
-			Tag:  tag,
-			Path: exportedFiles[tag],
-		})
-	}
+	deapexerProperties.ExportedFiles = android.SortedUniqueStrings(exportedFiles)
 
 	props := struct {
 		Name          *string
@@ -640,6 +643,10 @@
 // incorrectly.
 func (t exportedDependencyTag) ExcludeFromVisibilityEnforcement() {}
 
+func (t exportedDependencyTag) RequiresFilesFromPrebuiltApex() {}
+
+var _ android.RequiresFilesFromPrebuiltApexTag = exportedDependencyTag{}
+
 var (
 	exportedJavaLibTag               = exportedDependencyTag{name: "exported_java_libs"}
 	exportedBootclasspathFragmentTag = exportedDependencyTag{name: "exported_bootclasspath_fragments"}
diff --git a/apex/systemserver_classpath_fragment_test.go b/apex/systemserver_classpath_fragment_test.go
index 95b6e23..537f51d 100644
--- a/apex/systemserver_classpath_fragment_test.go
+++ b/apex/systemserver_classpath_fragment_test.go
@@ -76,3 +76,54 @@
 		`mysystemserverclasspathfragment`,
 	})
 }
+
+func TestSystemserverclasspathFragmentNoGeneratedProto(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		prepareForTestWithSystemserverclasspathFragment,
+		prepareForTestWithMyapex,
+	).RunTestWithBp(t, `
+		apex {
+			name: "myapex",
+			key: "myapex.key",
+			systemserverclasspath_fragments: [
+				"mysystemserverclasspathfragment",
+			],
+			updatable: false,
+		}
+
+		apex_key {
+			name: "myapex.key",
+			public_key: "testkey.avbpubkey",
+			private_key: "testkey.pem",
+		}
+
+		java_library {
+			name: "foo",
+			srcs: ["b.java"],
+			installable: true,
+			apex_available: [
+				"myapex",
+			],
+		}
+
+		systemserverclasspath_fragment {
+			name: "mysystemserverclasspathfragment",
+			generate_classpaths_proto: false,
+			contents: [
+				"foo",
+			],
+			apex_available: [
+				"myapex",
+			],
+		}
+	`)
+
+	ensureExactContents(t, result.TestContext, "myapex", "android_common_myapex_image", []string{
+		"javalib/foo.jar",
+	})
+
+	java.CheckModuleDependencies(t, result.TestContext, "myapex", "android_common_myapex_image", []string{
+		`myapex.key`,
+		`mysystemserverclasspathfragment`,
+	})
+}
diff --git a/bazel/properties.go b/bazel/properties.go
index 7093d6c..0dd47da 100644
--- a/bazel/properties.go
+++ b/bazel/properties.go
@@ -19,6 +19,7 @@
 	"path/filepath"
 	"regexp"
 	"sort"
+	"strings"
 )
 
 // BazelTargetModuleProperties contain properties and metadata used for
@@ -33,6 +34,10 @@
 
 const BazelTargetModuleNamePrefix = "__bp2build__"
 
+func StripNamePrefix(moduleName string) string {
+	return strings.TrimPrefix(moduleName, BazelTargetModuleNamePrefix)
+}
+
 var productVariableSubstitutionPattern = regexp.MustCompile("%(d|s)")
 
 // Label is used to represent a Bazel compatible Label. Also stores the original
diff --git a/bp2build/Android.bp b/bp2build/Android.bp
index 3abbc4c..0e6030e 100644
--- a/bp2build/Android.bp
+++ b/bp2build/Android.bp
@@ -11,6 +11,7 @@
         "build_conversion.go",
         "bzl_conversion.go",
         "configurability.go",
+        "compatibility.go",
         "constants.go",
         "conversion.go",
         "metrics.go",
diff --git a/bp2build/bp2build.go b/bp2build/bp2build.go
index ee36982..06a7306 100644
--- a/bp2build/bp2build.go
+++ b/bp2build/bp2build.go
@@ -29,12 +29,12 @@
 	bp2buildDir := android.PathForOutput(ctx, "bp2build")
 	android.RemoveAllOutputDir(bp2buildDir)
 
-	buildToTargets, metrics := GenerateBazelTargets(ctx, true)
+	buildToTargets, metrics, compatLayer := GenerateBazelTargets(ctx, true)
 	bp2buildFiles := CreateBazelFiles(nil, buildToTargets, ctx.mode)
 	writeFiles(ctx, bp2buildDir, bp2buildFiles)
 
 	soongInjectionDir := android.PathForOutput(ctx, bazel.SoongInjectionDirName)
-	writeFiles(ctx, soongInjectionDir, CreateSoongInjectionFiles())
+	writeFiles(ctx, soongInjectionDir, CreateSoongInjectionFiles(compatLayer))
 
 	return metrics
 }
diff --git a/bp2build/build_conversion.go b/bp2build/build_conversion.go
index a1e0424..96a8b09 100644
--- a/bp2build/build_conversion.go
+++ b/bp2build/build_conversion.go
@@ -32,6 +32,7 @@
 
 type BazelTarget struct {
 	name            string
+	packageName     string
 	content         string
 	ruleClass       string
 	bzlLoadLocation string
@@ -44,6 +45,16 @@
 	return t.bzlLoadLocation != ""
 }
 
+// Label is the fully qualified Bazel label constructed from the BazelTarget's
+// package name and target name.
+func (t BazelTarget) Label() string {
+	if t.packageName == "." {
+		return "//:" + t.name
+	} else {
+		return "//" + t.packageName + ":" + t.name
+	}
+}
+
 // BazelTargets is a typedef for a slice of BazelTarget objects.
 type BazelTargets []BazelTarget
 
@@ -213,7 +224,7 @@
 	return attributes
 }
 
-func GenerateBazelTargets(ctx *CodegenContext, generateFilegroups bool) (map[string]BazelTargets, CodegenMetrics) {
+func GenerateBazelTargets(ctx *CodegenContext, generateFilegroups bool) (map[string]BazelTargets, CodegenMetrics, CodegenCompatLayer) {
 	buildFileToTargets := make(map[string]BazelTargets)
 	buildFileToAppend := make(map[string]bool)
 
@@ -222,6 +233,10 @@
 		RuleClassCount: make(map[string]int),
 	}
 
+	compatLayer := CodegenCompatLayer{
+		NameToLabelMap: make(map[string]string),
+	}
+
 	dirs := make(map[string]bool)
 
 	bpCtx := ctx.Context()
@@ -236,6 +251,7 @@
 			if b, ok := m.(android.Bazelable); ok && b.HasHandcraftedLabel() {
 				metrics.handCraftedTargetCount += 1
 				metrics.TotalModuleCount += 1
+				compatLayer.AddNameToLabelEntry(m.Name(), b.HandcraftedLabel())
 				pathToBuildFile := getBazelPackagePath(b)
 				// We are using the entire contents of handcrafted build file, so if multiple targets within
 				// a package have handcrafted targets, we only want to include the contents one time.
@@ -253,6 +269,7 @@
 			} else if btm, ok := m.(android.BazelTargetModule); ok {
 				t = generateBazelTarget(bpCtx, m, btm)
 				metrics.RuleClassCount[t.ruleClass] += 1
+				compatLayer.AddNameToLabelEntry(m.Name(), t.Label())
 			} else {
 				metrics.TotalModuleCount += 1
 				return
@@ -283,7 +300,7 @@
 		}
 	}
 
-	return buildFileToTargets, metrics
+	return buildFileToTargets, metrics, compatLayer
 }
 
 func getBazelPackagePath(b android.Bazelable) string {
@@ -324,6 +341,7 @@
 	targetName := targetNameForBp2Build(ctx, m)
 	return BazelTarget{
 		name:            targetName,
+		packageName:     ctx.ModuleDir(m),
 		ruleClass:       ruleClass,
 		bzlLoadLocation: bzlLoadLocation,
 		content: fmt.Sprintf(
diff --git a/bp2build/build_conversion_test.go b/bp2build/build_conversion_test.go
index 33609af..0e52f2a 100644
--- a/bp2build/build_conversion_test.go
+++ b/bp2build/build_conversion_test.go
@@ -1398,14 +1398,14 @@
 			moduleTypeUnderTestFactory:         android.FileGroupFactory,
 			moduleTypeUnderTestBp2BuildMutator: android.FilegroupBp2Build,
 			bp: `filegroup {
-    name: "fg_foo",
-    bazel_module: { label: "//other:fg_foo" },
-}
+		    name: "fg_foo",
+		    bazel_module: { label: "//other:fg_foo" },
+		}
 
-filegroup {
-    name: "foo",
-    bazel_module: { label: "//other:foo" },
-}`,
+		filegroup {
+		    name: "foo",
+		    bazel_module: { label: "//other:foo" },
+		}`,
 			expectedBazelTargets: []string{
 				`// BUILD file`,
 			},
@@ -1414,25 +1414,31 @@
 			},
 		},
 		{
-			description:                        "filegroup bazel_module.label and bp2build",
+			description:                        "filegroup bazel_module.label and bp2build in subdir",
 			moduleTypeUnderTest:                "filegroup",
 			moduleTypeUnderTestFactory:         android.FileGroupFactory,
 			moduleTypeUnderTestBp2BuildMutator: android.FilegroupBp2Build,
-			bp: `filegroup {
-    name: "fg_foo",
-    bazel_module: {
-      label: "//other:fg_foo",
-      bp2build_available: true,
-    },
-}`,
+			dir:                                "other",
+			bp:                                 ``,
+			fs: map[string]string{
+				"other/Android.bp": `filegroup {
+				name: "fg_foo",
+				bazel_module: {
+					bp2build_available: true,
+				},
+			}
+			filegroup {
+				name: "fg_bar",
+				bazel_module: {
+					label: "//other:fg_bar"
+				},
+			}`,
+				"other/BUILD.bazel": `// definition for fg_bar`,
+			},
 			expectedBazelTargets: []string{
 				`filegroup(
     name = "fg_foo",
-)`,
-				`// BUILD file`,
-			},
-			fs: map[string]string{
-				"other/BUILD.bazel": `// BUILD file`,
+)`, `// definition for fg_bar`,
 			},
 		},
 		{
@@ -1441,18 +1447,18 @@
 			moduleTypeUnderTestFactory:         android.FileGroupFactory,
 			moduleTypeUnderTestBp2BuildMutator: android.FilegroupBp2Build,
 			bp: `filegroup {
-    name: "fg_foo",
-    bazel_module: {
-      label: "//other:fg_foo",
-    },
-}
+		    name: "fg_foo",
+		    bazel_module: {
+		      label: "//other:fg_foo",
+		    },
+		}
 
-filegroup {
-    name: "fg_bar",
-    bazel_module: {
-      bp2build_available: true,
-    },
-}`,
+		filegroup {
+		    name: "fg_bar",
+		    bazel_module: {
+		      bp2build_available: true,
+		    },
+		}`,
 			expectedBazelTargets: []string{
 				`filegroup(
     name = "fg_bar",
diff --git a/bp2build/compatibility.go b/bp2build/compatibility.go
new file mode 100644
index 0000000..5baa524
--- /dev/null
+++ b/bp2build/compatibility.go
@@ -0,0 +1,31 @@
+package bp2build
+
+import (
+	"android/soong/bazel"
+	"fmt"
+)
+
+// Data from the code generation process that is used to improve compatibility
+// between build systems.
+type CodegenCompatLayer struct {
+	// A map from the original module name to the generated/handcrafted Bazel
+	// label for legacy build systems to be able to build a fully-qualified
+	// Bazel target from an unique module name.
+	NameToLabelMap map[string]string
+}
+
+// Log an entry of module name -> Bazel target label.
+func (compatLayer CodegenCompatLayer) AddNameToLabelEntry(name, label string) {
+	// The module name may be prefixed with bazel.BazelTargetModuleNamePrefix if
+	// generated from bp2build.
+	name = bazel.StripNamePrefix(name)
+	if existingLabel, ok := compatLayer.NameToLabelMap[name]; ok {
+		panic(fmt.Errorf(
+			"Module '%s' maps to more than one Bazel target label: %s, %s. "+
+				"This shouldn't happen. It probably indicates a bug with the bp2build internals.",
+			name,
+			existingLabel,
+			label))
+	}
+	compatLayer.NameToLabelMap[name] = label
+}
diff --git a/bp2build/conversion.go b/bp2build/conversion.go
index bced4c1..75bc2b4 100644
--- a/bp2build/conversion.go
+++ b/bp2build/conversion.go
@@ -16,15 +16,31 @@
 	Contents string
 }
 
-func CreateSoongInjectionFiles() []BazelFile {
+func CreateSoongInjectionFiles(compatLayer CodegenCompatLayer) []BazelFile {
 	var files []BazelFile
 
-	files = append(files, newFile("cc_toolchain", "BUILD", "")) // Creates a //cc_toolchain package.
+	files = append(files, newFile("cc_toolchain", GeneratedBuildFileName, "")) // Creates a //cc_toolchain package.
 	files = append(files, newFile("cc_toolchain", "constants.bzl", config.BazelCcToolchainVars()))
 
+	files = append(files, newFile("module_name_to_label", GeneratedBuildFileName, nameToLabelAliases(compatLayer.NameToLabelMap)))
+
 	return files
 }
 
+func nameToLabelAliases(nameToLabelMap map[string]string) string {
+	ret := make([]string, len(nameToLabelMap))
+
+	for k, v := range nameToLabelMap {
+		// v is the fully qualified label rooted at '//'
+		ret = append(ret, fmt.Sprintf(
+			`alias(
+    name = "%s",
+    actual = "@%s",
+)`, k, v))
+	}
+	return strings.Join(ret, "\n\n")
+}
+
 func CreateBazelFiles(
 	ruleShims map[string]RuleShim,
 	buildToTargets map[string]BazelTargets,
diff --git a/bp2build/conversion_test.go b/bp2build/conversion_test.go
index 0931ff7..56ea589 100644
--- a/bp2build/conversion_test.go
+++ b/bp2build/conversion_test.go
@@ -80,17 +80,21 @@
 }
 
 func TestCreateBazelFiles_Bp2Build_CreatesDefaultFiles(t *testing.T) {
-	files := CreateSoongInjectionFiles()
+	files := CreateSoongInjectionFiles(CodegenCompatLayer{})
 
 	expectedFilePaths := []bazelFilepath{
 		{
 			dir:      "cc_toolchain",
-			basename: "BUILD",
+			basename: GeneratedBuildFileName,
 		},
 		{
 			dir:      "cc_toolchain",
 			basename: "constants.bzl",
 		},
+		{
+			dir:      "module_name_to_label",
+			basename: GeneratedBuildFileName,
+		},
 	}
 
 	if len(files) != len(expectedFilePaths) {
@@ -104,7 +108,7 @@
 			t.Errorf("Did not find expected file %s/%s", actualFile.Dir, actualFile.Basename)
 		}
 
-		if expectedFile.basename != "BUILD" && actualFile.Contents == "" {
+		if expectedFile.basename != GeneratedBuildFileName && actualFile.Contents == "" {
 			t.Errorf("Contents of %s unexpected empty.", actualFile)
 		}
 	}
diff --git a/bp2build/testing.go b/bp2build/testing.go
index 861f7d2..f3cd7f0 100644
--- a/bp2build/testing.go
+++ b/bp2build/testing.go
@@ -213,6 +213,6 @@
 // Helper method for tests to easily access the targets in a dir.
 func generateBazelTargetsForDir(codegenCtx *CodegenContext, dir string) BazelTargets {
 	// TODO: Set generateFilegroups to true and/or remove the generateFilegroups argument completely
-	buildFileToTargets, _ := GenerateBazelTargets(codegenCtx, false)
+	buildFileToTargets, _, _ := GenerateBazelTargets(codegenCtx, false)
 	return buildFileToTargets[dir]
 }
diff --git a/cc/cc.go b/cc/cc.go
index 49e218e..0c9f945 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -585,6 +585,7 @@
 	hostToolPath() android.OptionalPath
 	relativeInstallPath() string
 	makeUninstallable(mod *Module)
+	installInRoot() bool
 }
 
 // bazelHandler is the interface for a helper object related to deferring to Bazel for
@@ -1309,6 +1310,10 @@
 		Bool(c.sanitize.Properties.Sanitize.Config.Cfi_assembly_support)
 }
 
+func (c *Module) InstallInRoot() bool {
+	return c.installer != nil && c.installer.installInRoot()
+}
+
 type baseModuleContext struct {
 	android.BaseModuleContext
 	moduleContextImpl
diff --git a/cc/installer.go b/cc/installer.go
index e551c63..f95b493 100644
--- a/cc/installer.go
+++ b/cc/installer.go
@@ -25,6 +25,10 @@
 type InstallerProperties struct {
 	// install to a subdirectory of the default install path for the module
 	Relative_install_path *string `android:"arch_variant"`
+
+	// Install output directly in {partition}/, not in any subdir.  This is only intended for use by
+	// init_first_stage.
+	Install_in_root *bool `android:"arch_variant"`
 }
 
 type installLocation int
@@ -66,6 +70,11 @@
 	if ctx.toolchain().Is64Bit() && installer.dir64 != "" {
 		dir = installer.dir64
 	}
+
+	if installer.installInRoot() {
+		dir = ""
+	}
+
 	if ctx.Target().NativeBridge == android.NativeBridgeEnabled {
 		dir = filepath.Join(dir, ctx.Target().NativeBridgeRelativePath)
 	} else if !ctx.Host() && ctx.Config().HasMultilibConflict(ctx.Arch().ArchType) {
@@ -110,3 +119,7 @@
 func (installer *baseInstaller) makeUninstallable(mod *Module) {
 	mod.ModuleBase.MakeUninstallable()
 }
+
+func (installer *baseInstaller) installInRoot() bool {
+	return Bool(installer.Properties.Install_in_root)
+}
diff --git a/cc/pgo.go b/cc/pgo.go
index 95c9c2e..e78549e 100644
--- a/cc/pgo.go
+++ b/cc/pgo.go
@@ -56,7 +56,7 @@
 type PgoProperties struct {
 	Pgo struct {
 		Instrumentation    *bool
-		Sampling           *bool
+		Sampling           *bool   `android:"arch_variant"`
 		Profile_file       *string `android:"arch_variant"`
 		Benchmarks         []string
 		Enable_profile_use *bool `android:"arch_variant"`
diff --git a/cmd/soong_build/queryview.go b/cmd/soong_build/queryview.go
index e2ce772..a8602de 100644
--- a/cmd/soong_build/queryview.go
+++ b/cmd/soong_build/queryview.go
@@ -25,9 +25,10 @@
 func createBazelQueryView(ctx *bp2build.CodegenContext, bazelQueryViewDir string) error {
 	ruleShims := bp2build.CreateRuleShims(android.ModuleTypeFactories())
 
-	// Ignore metrics reporting for queryview, since queryview is already a full-repo
-	// conversion and can use data from bazel query directly.
-	buildToTargets, _ := bp2build.GenerateBazelTargets(ctx, true)
+	// Ignore metrics reporting and compat layers for queryview, since queryview
+	// is already a full-repo conversion and can use data from bazel query
+	// directly.
+	buildToTargets, _, _ := bp2build.GenerateBazelTargets(ctx, true)
 
 	filesToWrite := bp2build.CreateBazelFiles(ruleShims, buildToTargets, bp2build.QueryView)
 	for _, f := range filesToWrite {
diff --git a/java/Android.bp b/java/Android.bp
index 680f3a1..5952602 100644
--- a/java/Android.bp
+++ b/java/Android.bp
@@ -33,6 +33,7 @@
         "bootclasspath.go",
         "bootclasspath_fragment.go",
         "builder.go",
+        "classpath_element.go",
         "classpath_fragment.go",
         "device_host_converter.go",
         "dex.go",
diff --git a/java/base.go b/java/base.go
index 1daa108..a7cc58e 100644
--- a/java/base.go
+++ b/java/base.go
@@ -156,9 +156,11 @@
 		// List of java_plugin modules that provide extra errorprone checks.
 		Extra_check_modules []string
 
-		// Whether to run errorprone on a normal build. If this is false, errorprone
-		// will still be run if the RUN_ERROR_PRONE environment variable is true.
-		// Default false.
+		// This property can be in 3 states. When set to true, errorprone will
+		// be run during the regular build. When set to false, errorprone will
+		// never be run. When unset, errorprone will be run when the RUN_ERROR_PRONE
+		// environment variable is true. Setting this to false will improve build
+		// performance more than adding -XepDisableAllChecks in javacflags.
 		Enabled *bool
 	}
 
@@ -706,7 +708,8 @@
 	// javaVersion flag.
 	flags.javaVersion = getJavaVersion(ctx, String(j.properties.Java_version), android.SdkContext(j))
 
-	if ctx.Config().RunErrorProne() || Bool(j.properties.Errorprone.Enabled) {
+	epEnabled := j.properties.Errorprone.Enabled
+	if (ctx.Config().RunErrorProne() && epEnabled == nil) || Bool(epEnabled) {
 		if config.ErrorProneClasspath == nil && ctx.Config().TestProductVariables == nil {
 			ctx.ModuleErrorf("cannot build with Error Prone, missing external/error_prone?")
 		}
@@ -981,7 +984,7 @@
 			// If error-prone is enabled, enable errorprone flags on the regular
 			// build.
 			flags = enableErrorproneFlags(flags)
-		} else if ctx.Config().RunErrorProne() {
+		} else if ctx.Config().RunErrorProne() && j.properties.Errorprone.Enabled == nil {
 			// Otherwise, if the RUN_ERROR_PRONE environment variable is set, create
 			// a new jar file just for compiling with the errorprone compiler to.
 			// This is because we don't want to cause the java files to get completely
diff --git a/java/bootclasspath_fragment.go b/java/bootclasspath_fragment.go
index fb6b47e..4d23820 100644
--- a/java/bootclasspath_fragment.go
+++ b/java/bootclasspath_fragment.go
@@ -81,6 +81,9 @@
 // they were listed in java_libs.
 func (b bootclasspathFragmentContentDependencyTag) CopyDirectlyInAnyApex() {}
 
+// Contents of bootclasspath fragments require files from prebuilt apex files.
+func (b bootclasspathFragmentContentDependencyTag) RequiresFilesFromPrebuiltApex() {}
+
 // The tag used for the dependency between the bootclasspath_fragment module and its contents.
 var bootclasspathFragmentContentDepTag = bootclasspathFragmentContentDependencyTag{}
 
@@ -88,6 +91,7 @@
 var _ android.ReplaceSourceWithPrebuilt = bootclasspathFragmentContentDepTag
 var _ android.SdkMemberTypeDependencyTag = bootclasspathFragmentContentDepTag
 var _ android.CopyDirectlyInAnyApexTag = bootclasspathFragmentContentDepTag
+var _ android.RequiresFilesFromPrebuiltApexTag = bootclasspathFragmentContentDepTag
 
 func IsBootclasspathFragmentContentDepTag(tag blueprint.DependencyTag) bool {
 	return tag == bootclasspathFragmentContentDepTag
@@ -132,6 +136,9 @@
 	ClasspathFragmentBase
 
 	properties bootclasspathFragmentProperties
+
+	// Collect the module directory for IDE info in java/jdeps.go.
+	modulePaths []string
 }
 
 // commonBootclasspathFragment defines the methods that are implemented by both source and prebuilt
@@ -144,10 +151,22 @@
 	// module cannot contribute to hidden API processing, e.g. because it is a prebuilt module in a
 	// versioned sdk.
 	produceHiddenAPIOutput(ctx android.ModuleContext, contents []android.Module, input HiddenAPIFlagInput) *HiddenAPIOutput
+
+	// produceBootImageFiles produces the boot image (i.e. .art, .oat and .vdex) files for each of the
+	// required android.ArchType values in the returned map.
+	//
+	// It must return nil if the boot image files cannot be produced for whatever reason.
+	produceBootImageFiles(ctx android.ModuleContext, imageConfig *bootImageConfig, contents []android.Module) bootImageFilesByArch
 }
 
 var _ commonBootclasspathFragment = (*BootclasspathFragmentModule)(nil)
 
+// bootImageFilesByArch is a map from android.ArchType to the paths to the boot image files.
+//
+// The paths include the .art, .oat and .vdex files, one for each of the modules from which the boot
+// image is created.
+type bootImageFilesByArch map[android.ArchType]android.Paths
+
 func bootclasspathFragmentFactory() android.Module {
 	m := &BootclasspathFragmentModule{}
 	m.AddProperties(&m.properties)
@@ -285,7 +304,7 @@
 	modules android.ConfiguredJarList
 
 	// Map from arch type to the boot image files.
-	bootImageFilesByArch map[android.ArchType]android.OutputPaths
+	bootImageFilesByArch bootImageFilesByArch
 
 	// Map from the base module name (without prebuilt_ prefix) of a fragment's contents module to the
 	// hidden API encoded dex jar path.
@@ -299,7 +318,7 @@
 // Get a map from ArchType to the associated boot image's contents for Android.
 //
 // Extension boot images only return their own files, not the files of the boot images they extend.
-func (i BootclasspathFragmentApexContentInfo) AndroidBootImageFilesByArchType() map[android.ArchType]android.OutputPaths {
+func (i BootclasspathFragmentApexContentInfo) AndroidBootImageFilesByArchType() bootImageFilesByArch {
 	return i.bootImageFilesByArch
 }
 
@@ -386,6 +405,9 @@
 	// Generate classpaths.proto config
 	b.generateClasspathProtoBuildActions(ctx)
 
+	// Collect the module directory for IDE info in java/jdeps.go.
+	b.modulePaths = append(b.modulePaths, ctx.ModuleDir())
+
 	// Gather the bootclasspath fragment's contents.
 	var contents []android.Module
 	ctx.VisitDirectDeps(func(module android.Module) {
@@ -409,17 +431,52 @@
 		// Perform hidden API processing.
 		hiddenAPIOutput := b.generateHiddenAPIBuildActions(ctx, contents, fragments)
 
+		var bootImageFilesByArch bootImageFilesByArch
+		if imageConfig != nil {
+			// Delegate the production of the boot image files to a module type specific method.
+			common := ctx.Module().(commonBootclasspathFragment)
+			bootImageFilesByArch = common.produceBootImageFiles(ctx, imageConfig, contents)
+
+			if shouldCopyBootFilesToPredefinedLocations(ctx, imageConfig) {
+				// Copy the dex jars of this fragment's content modules to their predefined locations.
+				copyBootJarsToPredefinedLocations(ctx, hiddenAPIOutput.EncodedBootDexFilesByModule, imageConfig.dexPathsByModule)
+			}
+		}
+
 		// A prebuilt fragment cannot contribute to an apex.
 		if !android.IsModulePrebuilt(ctx.Module()) {
 			// Provide the apex content info.
-			b.provideApexContentInfo(ctx, imageConfig, contents, hiddenAPIOutput)
+			b.provideApexContentInfo(ctx, imageConfig, hiddenAPIOutput, bootImageFilesByArch)
 		}
 	}
 }
 
+// shouldCopyBootFilesToPredefinedLocations determines whether the current module should copy boot
+// files, e.g. boot dex jars or boot image files, to the predefined location expected by the rest
+// of the build.
+//
+// This ensures that only a single module will copy its files to the image configuration.
+func shouldCopyBootFilesToPredefinedLocations(ctx android.ModuleContext, imageConfig *bootImageConfig) bool {
+	// Bootclasspath fragment modules that are for the platform do not produce boot related files.
+	apexInfo := ctx.Provider(android.ApexInfoProvider).(android.ApexInfo)
+	if apexInfo.IsForPlatform() {
+		return false
+	}
+
+	// If the image configuration has no modules specified then it means that the build has been
+	// configured to build something other than a boot image, e.g. an sdk, so do not try and copy the
+	// files.
+	if imageConfig.modules.Len() == 0 {
+		return false
+	}
+
+	// Only copy files from the module that is preferred.
+	return isActiveModule(ctx.Module())
+}
+
 // provideApexContentInfo creates, initializes and stores the apex content info for use by other
 // modules.
-func (b *BootclasspathFragmentModule) provideApexContentInfo(ctx android.ModuleContext, imageConfig *bootImageConfig, contents []android.Module, hiddenAPIOutput *HiddenAPIOutput) {
+func (b *BootclasspathFragmentModule) provideApexContentInfo(ctx android.ModuleContext, imageConfig *bootImageConfig, hiddenAPIOutput *HiddenAPIOutput, bootImageFilesByArch bootImageFilesByArch) {
 	// Construct the apex content info from the config.
 	info := BootclasspathFragmentApexContentInfo{
 		// Populate the apex content info with paths to the dex jars.
@@ -428,28 +485,10 @@
 
 	if imageConfig != nil {
 		info.modules = imageConfig.modules
-
-		if !SkipDexpreoptBootJars(ctx) {
-			// Force the GlobalSoongConfig to be created and cached for use by the dex_bootjars
-			// GenerateSingletonBuildActions method as it cannot create it for itself.
-			dexpreopt.GetGlobalSoongConfig(ctx)
-
-			// Only generate the boot image if the configuration does not skip it.
-			if b.generateBootImageBuildActions(ctx, contents, imageConfig) {
-				// Allow the apex to access the boot image files.
-				files := map[android.ArchType]android.OutputPaths{}
-				for _, variant := range imageConfig.variants {
-					// We also generate boot images for host (for testing), but we don't need those in the apex.
-					// TODO(b/177892522) - consider changing this to check Os.OsClass = android.Device
-					if variant.target.Os == android.Android {
-						files[variant.target.Arch.ArchType] = variant.imagesDeps
-					}
-				}
-				info.bootImageFilesByArch = files
-			}
-		}
 	}
 
+	info.bootImageFilesByArch = bootImageFilesByArch
+
 	// Make the apex content info available for other modules.
 	ctx.SetProvider(BootclasspathFragmentApexContentInfoProvider, info)
 }
@@ -586,7 +625,6 @@
 // createHiddenAPIFlagInput creates a HiddenAPIFlagInput struct and initializes it with information derived
 // from the properties on this module and its dependencies.
 func (b *BootclasspathFragmentModule) createHiddenAPIFlagInput(ctx android.ModuleContext, contents []android.Module, fragments []android.Module) HiddenAPIFlagInput {
-
 	// Merge the HiddenAPIInfo from all the fragment dependencies.
 	dependencyHiddenApiInfo := newHiddenAPIInfo()
 	dependencyHiddenApiInfo.mergeFromFragmentDeps(ctx, fragments)
@@ -614,6 +652,30 @@
 	return hiddenAPIRulesForBootclasspathFragment(ctx, contents, input)
 }
 
+// produceBootImageFiles builds the boot image files from the source if it is required.
+func (b *BootclasspathFragmentModule) produceBootImageFiles(ctx android.ModuleContext, imageConfig *bootImageConfig, contents []android.Module) bootImageFilesByArch {
+	if SkipDexpreoptBootJars(ctx) {
+		return nil
+	}
+
+	// Force the GlobalSoongConfig to be created and cached for use by the dex_bootjars
+	// GenerateSingletonBuildActions method as it cannot create it for itself.
+	dexpreopt.GetGlobalSoongConfig(ctx)
+
+	// Only generate the boot image if the configuration does not skip it.
+	if !b.generateBootImageBuildActions(ctx, contents, imageConfig) {
+		return nil
+	}
+
+	// Only make the files available to an apex if they were actually generated.
+	files := bootImageFilesByArch{}
+	for _, variant := range imageConfig.apexVariants() {
+		files[variant.target.Arch.ArchType] = variant.imagesDeps.Paths()
+	}
+
+	return files
+}
+
 // generateBootImageBuildActions generates ninja rules to create the boot image if required for this
 // module.
 //
@@ -635,10 +697,6 @@
 		return false
 	}
 
-	// Copy the dex jars of this fragment's content modules to their predefined locations.
-	bootDexJarByModule := extractEncodedDexJarsFromModules(ctx, contents)
-	copyBootJarsToPredefinedLocations(ctx, bootDexJarByModule, imageConfig.dexPathsByModule)
-
 	// Build a profile for the image config and then use that to build the boot image.
 	profile := bootImageProfileRule(ctx, imageConfig)
 	buildBootImage(ctx, imageConfig, profile)
@@ -646,6 +704,12 @@
 	return true
 }
 
+// Collect information for opening IDE project files in java/jdeps.go.
+func (b *BootclasspathFragmentModule) IDEInfo(dpInfo *android.IdeInfo) {
+	dpInfo.Deps = append(dpInfo.Deps, b.properties.Contents...)
+	dpInfo.Paths = append(dpInfo.Paths, b.modulePaths...)
+}
+
 type bootclasspathFragmentMemberType struct {
 	android.SdkMemberTypeBase
 }
@@ -855,8 +919,88 @@
 	return &output
 }
 
+// produceBootImageFiles extracts the boot image files from the APEX if available.
+func (module *prebuiltBootclasspathFragmentModule) produceBootImageFiles(ctx android.ModuleContext, imageConfig *bootImageConfig, contents []android.Module) bootImageFilesByArch {
+	if !shouldCopyBootFilesToPredefinedLocations(ctx, imageConfig) {
+		return nil
+	}
+
+	var deapexerModule android.Module
+	ctx.VisitDirectDeps(func(module android.Module) {
+		tag := ctx.OtherModuleDependencyTag(module)
+		// Save away the `deapexer` module on which this depends, if any.
+		if tag == android.DeapexerTag {
+			deapexerModule = module
+		}
+	})
+
+	if deapexerModule == nil {
+		// This should never happen as a variant for a prebuilt_apex is only created if the
+		// deapexer module has been configured to export the dex implementation jar for this module.
+		ctx.ModuleErrorf("internal error: module does not depend on a `deapexer` module")
+		return nil
+	}
+
+	di := ctx.OtherModuleProvider(deapexerModule, android.DeapexerProvider).(android.DeapexerInfo)
+	for _, variant := range imageConfig.apexVariants() {
+		arch := variant.target.Arch.ArchType
+		for _, toPath := range variant.imagesDeps {
+			apexRelativePath := apexRootRelativePathToBootImageFile(arch, toPath.Base())
+			// Get the path to the file that the deapexer extracted from the prebuilt apex file.
+			fromPath := di.PrebuiltExportPath(apexRelativePath)
+
+			// Copy the file to the predefined location.
+			ctx.Build(pctx, android.BuildParams{
+				Rule:   android.Cp,
+				Input:  fromPath,
+				Output: toPath,
+			})
+		}
+	}
+
+	// The returned files will be made available to APEXes that include a bootclasspath_fragment.
+	// However, as a prebuilt_bootclasspath_fragment can never contribute to an APEX there is no point
+	// in returning any files.
+	return nil
+}
+
 var _ commonBootclasspathFragment = (*prebuiltBootclasspathFragmentModule)(nil)
 
+// createBootImageTag creates the tag to uniquely identify the boot image file among all of the
+// files that a module requires from the prebuilt .apex file.
+func createBootImageTag(arch android.ArchType, baseName string) string {
+	tag := fmt.Sprintf(".bootimage-%s-%s", arch, baseName)
+	return tag
+}
+
+// RequiredFilesFromPrebuiltApex returns the list of all files the prebuilt_bootclasspath_fragment
+// requires from a prebuilt .apex file.
+//
+// If there is no image config associated with this fragment then it returns nil. Otherwise, it
+// returns the files that are listed in the image config.
+func (module *prebuiltBootclasspathFragmentModule) RequiredFilesFromPrebuiltApex(ctx android.BaseModuleContext) []string {
+	imageConfig := module.getImageConfig(ctx)
+	if imageConfig != nil {
+		// Add the boot image files, e.g. .art, .oat and .vdex files.
+		files := []string{}
+		for _, variant := range imageConfig.apexVariants() {
+			arch := variant.target.Arch.ArchType
+			for _, path := range variant.imagesDeps.Paths() {
+				base := path.Base()
+				files = append(files, apexRootRelativePathToBootImageFile(arch, base))
+			}
+		}
+		return files
+	}
+	return nil
+}
+
+func apexRootRelativePathToBootImageFile(arch android.ArchType, base string) string {
+	return filepath.Join("javalib", arch.String(), base)
+}
+
+var _ android.RequiredFilesFromPrebuiltApex = (*prebuiltBootclasspathFragmentModule)(nil)
+
 func prebuiltBootclasspathFragmentFactory() android.Module {
 	m := &prebuiltBootclasspathFragmentModule{}
 	m.AddProperties(&m.properties, &m.prebuiltProperties)
diff --git a/java/classpath_element.go b/java/classpath_element.go
new file mode 100644
index 0000000..753e7f8
--- /dev/null
+++ b/java/classpath_element.go
@@ -0,0 +1,229 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package java
+
+import (
+	"fmt"
+	"strings"
+
+	"android/soong/android"
+	"github.com/google/blueprint"
+)
+
+// Supports constructing a list of ClasspathElement from a set of fragments and modules.
+
+// ClasspathElement represents a component that contributes to a classpath. That can be
+// either a java module or a classpath fragment module.
+type ClasspathElement interface {
+	Module() android.Module
+	String() string
+}
+
+type ClasspathElements []ClasspathElement
+
+// ClasspathFragmentElement is a ClasspathElement that encapsulates a classpath fragment module.
+type ClasspathFragmentElement struct {
+	Fragment android.Module
+	Contents []android.Module
+}
+
+func (b *ClasspathFragmentElement) Module() android.Module {
+	return b.Fragment
+}
+
+func (b *ClasspathFragmentElement) String() string {
+	contents := []string{}
+	for _, module := range b.Contents {
+		contents = append(contents, module.String())
+	}
+	return fmt.Sprintf("fragment(%s, %s)", b.Fragment, strings.Join(contents, ", "))
+}
+
+var _ ClasspathElement = (*ClasspathFragmentElement)(nil)
+
+// ClasspathLibraryElement is a ClasspathElement that encapsulates a java library.
+type ClasspathLibraryElement struct {
+	Library android.Module
+}
+
+func (b *ClasspathLibraryElement) Module() android.Module {
+	return b.Library
+}
+
+func (b *ClasspathLibraryElement) String() string {
+	return fmt.Sprintf("library{%s}", b.Library)
+}
+
+var _ ClasspathElement = (*ClasspathLibraryElement)(nil)
+
+// ClasspathElementContext defines the context methods needed by CreateClasspathElements
+type ClasspathElementContext interface {
+	OtherModuleHasProvider(m blueprint.Module, provider blueprint.ProviderKey) bool
+	OtherModuleProvider(m blueprint.Module, provider blueprint.ProviderKey) interface{}
+	ModuleErrorf(fmt string, args ...interface{})
+}
+
+// CreateClasspathElements creates a list of ClasspathElement objects from a list of libraries and
+// a list of fragments.
+//
+// The libraries parameter contains the set of libraries from which the classpath is constructed.
+// The fragments parameter contains the classpath fragment modules whose contents are libraries that
+// are part of the classpath. Each library in the libraries parameter may be part of a fragment. The
+// determination as to which libraries belong to fragments and which do not is based on the apex to
+// which they belong, if any.
+//
+// Every fragment in the fragments list must be part of one or more apexes and each apex is assumed
+// to contain only a single fragment from the fragments list. A library in the libraries parameter
+// that is part of an apex must be provided by a classpath fragment in the corresponding apex.
+//
+// This will return a ClasspathElements list that contains a ClasspathElement for each standalone
+// library and each fragment. The order of the elements in the list is such that if the list was
+// flattened into a list of library modules that it would result in the same list or modules as the
+// input libraries. Flattening the list can be done by replacing each ClasspathFragmentElement in
+// the list with its Contents field.
+//
+// Requirements/Assumptions:
+// * A fragment can be associated with more than one apex but each apex must only be associated with
+//   a single fragment from the fragments list.
+// * All of a fragment's contents must appear as a contiguous block in the same order in the
+//   libraries list.
+// * Each library must only appear in a single fragment.
+//
+// The apex is used to identify which libraries belong to which fragment. First a mapping is created
+// from apex to fragment. Then the libraries are iterated over and any library in an apex is
+// associated with an element for the fragment to which it belongs. Otherwise, the libraries are
+// standalone and have their own element.
+//
+// e.g. Given the following input:
+//     libraries: com.android.art:core-oj, com.android.art:core-libart, framework, ext
+//     fragments: com.android.art:art-bootclasspath-fragment
+//
+// Then this will return:
+//     ClasspathFragmentElement(art-bootclasspath-fragment, [core-oj, core-libart]),
+//     ClasspathLibraryElement(framework),
+//     ClasspathLibraryElement(ext),
+func CreateClasspathElements(ctx ClasspathElementContext, libraries []android.Module, fragments []android.Module) ClasspathElements {
+	// Create a map from apex name to the fragment module. This makes it easy to find the fragment
+	// associated with a particular apex.
+	apexToFragment := map[string]android.Module{}
+	for _, fragment := range fragments {
+		if !ctx.OtherModuleHasProvider(fragment, android.ApexInfoProvider) {
+			ctx.ModuleErrorf("fragment %s is not part of an apex", fragment)
+			continue
+		}
+
+		apexInfo := ctx.OtherModuleProvider(fragment, android.ApexInfoProvider).(android.ApexInfo)
+		for _, apex := range apexInfo.InApexVariants {
+			if existing, ok := apexToFragment[apex]; ok {
+				ctx.ModuleErrorf("apex %s has multiple fragments, %s and %s", apex, fragment, existing)
+				continue
+			}
+			apexToFragment[apex] = fragment
+		}
+	}
+
+	fragmentToElement := map[android.Module]*ClasspathFragmentElement{}
+	elements := []ClasspathElement{}
+	var currentElement ClasspathElement
+
+skipLibrary:
+	// Iterate over the libraries to construct the ClasspathElements list.
+	for _, library := range libraries {
+		var element ClasspathElement
+		if ctx.OtherModuleHasProvider(library, android.ApexInfoProvider) {
+			apexInfo := ctx.OtherModuleProvider(library, android.ApexInfoProvider).(android.ApexInfo)
+
+			var fragment android.Module
+
+			// Make sure that the library is in only one fragment of the classpath.
+			for _, apex := range apexInfo.InApexVariants {
+				if f, ok := apexToFragment[apex]; ok {
+					if fragment == nil {
+						// This is the first fragment so just save it away.
+						fragment = f
+					} else if f != fragment {
+						// This apex variant of the library is in a different fragment.
+						ctx.ModuleErrorf("library %s is in two separate fragments, %s and %s", library, fragment, f)
+						// Skip over this library entirely as otherwise the resulting classpath elements would
+						// be invalid.
+						continue skipLibrary
+					}
+				} else {
+					// There is no fragment associated with the library's apex.
+				}
+			}
+
+			if fragment == nil {
+				ctx.ModuleErrorf("library %s is from apexes %s which have no corresponding fragment in %s",
+					library, apexInfo.InApexVariants, fragments)
+				// Skip over this library entirely as otherwise the resulting classpath elements would
+				// be invalid.
+				continue skipLibrary
+			} else if existingFragmentElement, ok := fragmentToElement[fragment]; ok {
+				// This library is in a fragment element that has already been added.
+
+				// If the existing fragment element is still the current element then this library is
+				// contiguous with other libraries in that fragment so there is nothing more to do.
+				// Otherwise this library is not contiguous with other libraries in the same fragment which
+				// is an error.
+				if existingFragmentElement != currentElement {
+					separator := ""
+					if fragmentElement, ok := currentElement.(*ClasspathFragmentElement); ok {
+						separator = fmt.Sprintf("libraries from fragment %s like %s", fragmentElement.Fragment, fragmentElement.Contents[0])
+					} else {
+						libraryElement := currentElement.(*ClasspathLibraryElement)
+						separator = fmt.Sprintf("library %s", libraryElement.Library)
+					}
+
+					// Get the library that precedes this library in the fragment. That is the last library as
+					// this library has not yet been added.
+					precedingLibraryInFragment := existingFragmentElement.Contents[len(existingFragmentElement.Contents)-1]
+					ctx.ModuleErrorf("libraries from the same fragment must be contiguous, however %s and %s from fragment %s are separated by %s",
+						precedingLibraryInFragment, library, fragment, separator)
+				}
+
+				// Add this library to the fragment element's contents.
+				existingFragmentElement.Contents = append(existingFragmentElement.Contents, library)
+			} else {
+				// This is the first library in this fragment so add a new element for the fragment,
+				// including the library.
+				fragmentElement := &ClasspathFragmentElement{
+					Fragment: fragment,
+					Contents: []android.Module{library},
+				}
+
+				// Store it away so we can detect when attempting to create another element for the same
+				// fragment.
+				fragmentToElement[fragment] = fragmentElement
+				element = fragmentElement
+			}
+		} else {
+			// The library is from the platform so just add an element for it.
+			element = &ClasspathLibraryElement{Library: library}
+		}
+
+		// If no element was created then it means that the library has been added to an existing
+		// fragment element so the list of elements and current element are unaffected.
+		if element != nil {
+			// Add the element to the list and make it the current element for the next iteration.
+			elements = append(elements, element)
+			currentElement = element
+		}
+	}
+
+	return elements
+}
diff --git a/java/classpath_fragment.go b/java/classpath_fragment.go
index 4c1e749..3d72580 100644
--- a/java/classpath_fragment.go
+++ b/java/classpath_fragment.go
@@ -19,6 +19,7 @@
 import (
 	"fmt"
 	"github.com/google/blueprint"
+	"github.com/google/blueprint/proptools"
 	"strings"
 
 	"android/soong/android"
@@ -44,6 +45,11 @@
 }
 
 type classpathFragmentProperties struct {
+	// Whether to generated classpaths.proto config instance for the fragment. If the config is not
+	// generated, then relevant boot jars are added to platform classpath, i.e. platform_bootclasspath
+	// or platform_systemserverclasspath. This is useful for non-updatable APEX boot jars, to keep
+	// them as part of dexopt on device. Defaults to true.
+	Generate_classpaths_proto *bool
 }
 
 // classpathFragment interface is implemented by a module that contributes jars to a *CLASSPATH
@@ -101,24 +107,28 @@
 }
 
 func (c *ClasspathFragmentBase) generateClasspathProtoBuildActions(ctx android.ModuleContext, jars []classpathJar) {
-	outputFilename := strings.ToLower(c.classpathType.String()) + ".pb"
-	c.outputFilepath = android.PathForModuleOut(ctx, outputFilename).OutputPath
-	c.installDirPath = android.PathForModuleInstall(ctx, "etc", "classpaths")
+	generateProto := proptools.BoolDefault(c.properties.Generate_classpaths_proto, true)
+	if generateProto {
+		outputFilename := strings.ToLower(c.classpathType.String()) + ".pb"
+		c.outputFilepath = android.PathForModuleOut(ctx, outputFilename).OutputPath
+		c.installDirPath = android.PathForModuleInstall(ctx, "etc", "classpaths")
 
-	generatedJson := android.PathForModuleOut(ctx, outputFilename+".json")
-	writeClasspathsJson(ctx, generatedJson, jars)
+		generatedJson := android.PathForModuleOut(ctx, outputFilename+".json")
+		writeClasspathsJson(ctx, generatedJson, jars)
 
-	rule := android.NewRuleBuilder(pctx, ctx)
-	rule.Command().
-		BuiltTool("conv_classpaths_proto").
-		Flag("encode").
-		Flag("--format=json").
-		FlagWithInput("--input=", generatedJson).
-		FlagWithOutput("--output=", c.outputFilepath)
+		rule := android.NewRuleBuilder(pctx, ctx)
+		rule.Command().
+			BuiltTool("conv_classpaths_proto").
+			Flag("encode").
+			Flag("--format=json").
+			FlagWithInput("--input=", generatedJson).
+			FlagWithOutput("--output=", c.outputFilepath)
 
-	rule.Build("classpath_fragment", "Compiling "+c.outputFilepath.String())
+		rule.Build("classpath_fragment", "Compiling "+c.outputFilepath.String())
+	}
 
 	classpathProtoInfo := ClasspathFragmentProtoContentInfo{
+		ClasspathFragmentProtoGenerated:  generateProto,
 		ClasspathFragmentProtoInstallDir: c.installDirPath,
 		ClasspathFragmentProtoOutput:     c.outputFilepath,
 	}
@@ -164,6 +174,9 @@
 var ClasspathFragmentProtoContentInfoProvider = blueprint.NewProvider(ClasspathFragmentProtoContentInfo{})
 
 type ClasspathFragmentProtoContentInfo struct {
+	// Whether the classpaths.proto config is generated for the fragment.
+	ClasspathFragmentProtoGenerated bool
+
 	// ClasspathFragmentProtoOutput is an output path for the generated classpaths.proto config of this module.
 	//
 	// The file should be copied to a relevant place on device, see ClasspathFragmentProtoInstallDir
diff --git a/java/dexpreopt_bootjars.go b/java/dexpreopt_bootjars.go
index dc8df5e..bb85784 100644
--- a/java/dexpreopt_bootjars.go
+++ b/java/dexpreopt_bootjars.go
@@ -358,6 +358,19 @@
 	return ret
 }
 
+// apexVariants returns a list of all *bootImageVariant that could be included in an apex.
+func (image *bootImageConfig) apexVariants() []*bootImageVariant {
+	variants := []*bootImageVariant{}
+	for _, variant := range image.variants {
+		// We also generate boot images for host (for testing), but we don't need those in the apex.
+		// TODO(b/177892522) - consider changing this to check Os.OsClass = android.Device
+		if variant.target.Os == android.Android {
+			variants = append(variants, variant)
+		}
+	}
+	return variants
+}
+
 // Return boot image locations (as a list of symbolic paths).
 //
 // The image "location" is a symbolic path that, with multiarchitecture support, doesn't really
@@ -489,7 +502,7 @@
 	}
 }
 
-// buildBootImage takes a bootImageConfig, creates rules to build it, and returns the image.
+// buildBootImage takes a bootImageConfig, and creates rules to build it.
 func buildBootImage(ctx android.ModuleContext, image *bootImageConfig, profile android.WritablePath) {
 	var zipFiles android.Paths
 	for _, variant := range image.variants {
diff --git a/java/hiddenapi_monolithic.go b/java/hiddenapi_monolithic.go
index edf4235..8a83d10 100644
--- a/java/hiddenapi_monolithic.go
+++ b/java/hiddenapi_monolithic.go
@@ -43,22 +43,37 @@
 
 	// The paths to the generated all-flags.csv files.
 	AllFlagsPaths android.Paths
+
+	// The classes jars from the libraries on the platform bootclasspath.
+	ClassesJars android.Paths
 }
 
 // newMonolithicHiddenAPIInfo creates a new MonolithicHiddenAPIInfo from the flagFilesByCategory
 // plus information provided by each of the fragments.
-func newMonolithicHiddenAPIInfo(ctx android.ModuleContext, flagFilesByCategory FlagFilesByCategory, fragments []android.Module) MonolithicHiddenAPIInfo {
+func newMonolithicHiddenAPIInfo(ctx android.ModuleContext, flagFilesByCategory FlagFilesByCategory, classpathElements ClasspathElements) MonolithicHiddenAPIInfo {
 	monolithicInfo := MonolithicHiddenAPIInfo{}
 
 	monolithicInfo.FlagsFilesByCategory = flagFilesByCategory
 
-	// Merge all the information from the fragments. The fragments form a DAG so it is possible that
-	// this will introduce duplicates so they will be resolved after processing all the fragments.
-	for _, fragment := range fragments {
-		if ctx.OtherModuleHasProvider(fragment, HiddenAPIInfoProvider) {
-			info := ctx.OtherModuleProvider(fragment, HiddenAPIInfoProvider).(HiddenAPIInfo)
-			monolithicInfo.append(&info)
+	// Merge all the information from the classpathElements. The fragments form a DAG so it is possible that
+	// this will introduce duplicates so they will be resolved after processing all the classpathElements.
+	for _, element := range classpathElements {
+		var classesJars android.Paths
+		switch e := element.(type) {
+		case *ClasspathLibraryElement:
+			classesJars = retrieveClassesJarsFromModule(e.Module())
+
+		case *ClasspathFragmentElement:
+			fragment := e.Module()
+			if ctx.OtherModuleHasProvider(fragment, HiddenAPIInfoProvider) {
+				info := ctx.OtherModuleProvider(fragment, HiddenAPIInfoProvider).(HiddenAPIInfo)
+				monolithicInfo.append(&info)
+			}
+
+			classesJars = extractClassesJarsFromModules(e.Contents)
 		}
+
+		monolithicInfo.ClassesJars = append(monolithicInfo.ClassesJars, classesJars...)
 	}
 
 	// Dedup paths.
diff --git a/java/java.go b/java/java.go
index 2bbb5b1..ae8adf2 100644
--- a/java/java.go
+++ b/java/java.go
@@ -1309,7 +1309,7 @@
 
 			// Get the path of the dex implementation jar from the `deapexer` module.
 			di := ctx.OtherModuleProvider(deapexerModule, android.DeapexerProvider).(android.DeapexerInfo)
-			if dexOutputPath := di.PrebuiltExportPath(j.BaseModuleName(), ".dexjar"); dexOutputPath != nil {
+			if dexOutputPath := di.PrebuiltExportPath(apexRootRelativePathToJavaLib(j.BaseModuleName())); dexOutputPath != nil {
 				j.dexJarFile = dexOutputPath
 
 				// Initialize the hiddenapi structure.
@@ -1426,6 +1426,29 @@
 	return nil
 }
 
+// requiredFilesFromPrebuiltApexForImport returns information about the files that a java_import or
+// java_sdk_library_import with the specified base module name requires to be exported from a
+// prebuilt_apex/apex_set.
+func requiredFilesFromPrebuiltApexForImport(name string) []string {
+	// Add the dex implementation jar to the set of exported files.
+	return []string{
+		apexRootRelativePathToJavaLib(name),
+	}
+}
+
+// apexRootRelativePathToJavaLib returns the path, relative to the root of the apex's contents, for
+// the java library with the specified name.
+func apexRootRelativePathToJavaLib(name string) string {
+	return filepath.Join("javalib", name+".jar")
+}
+
+var _ android.RequiredFilesFromPrebuiltApex = (*Import)(nil)
+
+func (j *Import) RequiredFilesFromPrebuiltApex(_ android.BaseModuleContext) []string {
+	name := j.BaseModuleName()
+	return requiredFilesFromPrebuiltApexForImport(name)
+}
+
 // Add compile time check for interface implementation
 var _ android.IDEInfo = (*Import)(nil)
 var _ android.IDECustomizedModuleName = (*Import)(nil)
diff --git a/java/java_test.go b/java/java_test.go
index 78d9ab4..0f9965d 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -1409,7 +1409,7 @@
 	// Test that the errorprone plugins are passed to javac
 	expectedSubstring := "-Xplugin:ErrorProne"
 	if !strings.Contains(javac.Args["javacFlags"], expectedSubstring) {
-		t.Errorf("expected javacFlags to conain %q, got %q", expectedSubstring, javac.Args["javacFlags"])
+		t.Errorf("expected javacFlags to contain %q, got %q", expectedSubstring, javac.Args["javacFlags"])
 	}
 
 	// Modules with errorprone { enabled: true } will include errorprone checks
@@ -1420,3 +1420,67 @@
 		t.Errorf("expected errorprone build rule to not exist, but it did")
 	}
 }
+
+func TestErrorproneDisabled(t *testing.T) {
+	bp := `
+		java_library {
+			name: "foo",
+			srcs: ["a.java"],
+			errorprone: {
+				enabled: false,
+			},
+		}
+	`
+	ctx := android.GroupFixturePreparers(
+		PrepareForTestWithJavaDefaultModules,
+		android.FixtureMergeEnv(map[string]string{
+			"RUN_ERROR_PRONE": "true",
+		}),
+	).RunTestWithBp(t, bp)
+
+	javac := ctx.ModuleForTests("foo", "android_common").Description("javac")
+
+	// Test that the errorprone plugins are not passed to javac, like they would
+	// be if enabled was true.
+	expectedSubstring := "-Xplugin:ErrorProne"
+	if strings.Contains(javac.Args["javacFlags"], expectedSubstring) {
+		t.Errorf("expected javacFlags to not contain %q, got %q", expectedSubstring, javac.Args["javacFlags"])
+	}
+
+	// Check that no errorprone build rule is created, like there would be
+	// if enabled was unset and RUN_ERROR_PRONE was true.
+	errorprone := ctx.ModuleForTests("foo", "android_common").MaybeDescription("errorprone")
+	if errorprone.RuleParams.Description != "" {
+		t.Errorf("expected errorprone build rule to not exist, but it did")
+	}
+}
+
+func TestErrorproneEnabledOnlyByEnvironmentVariable(t *testing.T) {
+	bp := `
+		java_library {
+			name: "foo",
+			srcs: ["a.java"],
+		}
+	`
+	ctx := android.GroupFixturePreparers(
+		PrepareForTestWithJavaDefaultModules,
+		android.FixtureMergeEnv(map[string]string{
+			"RUN_ERROR_PRONE": "true",
+		}),
+	).RunTestWithBp(t, bp)
+
+	javac := ctx.ModuleForTests("foo", "android_common").Description("javac")
+	errorprone := ctx.ModuleForTests("foo", "android_common").Description("errorprone")
+
+	// Check that the errorprone plugins are not passed to javac, because they
+	// will instead be passed to the separate errorprone compilation
+	expectedSubstring := "-Xplugin:ErrorProne"
+	if strings.Contains(javac.Args["javacFlags"], expectedSubstring) {
+		t.Errorf("expected javacFlags to not contain %q, got %q", expectedSubstring, javac.Args["javacFlags"])
+	}
+
+	// Check that the errorprone plugin is enabled
+	if !strings.Contains(errorprone.Args["javacFlags"], expectedSubstring) {
+		t.Errorf("expected errorprone to contain %q, got %q", expectedSubstring, javac.Args["javacFlags"])
+	}
+}
diff --git a/java/legacy_core_platform_api_usage.go b/java/legacy_core_platform_api_usage.go
index 5949edd..8c401a7 100644
--- a/java/legacy_core_platform_api_usage.go
+++ b/java/legacy_core_platform_api_usage.go
@@ -20,6 +20,7 @@
 )
 
 var legacyCorePlatformApiModules = []string{
+	"ArcSettings",
 	"ahat-test-dump",
 	"android.car",
 	"android.test.mock",
@@ -42,6 +43,7 @@
 	"car-service-test-lib",
 	"car-service-test-static-lib",
 	"CertInstaller",
+	"com.qti.media.secureprocessor",
 	"ConnectivityManagerTest",
 	"ContactsProvider",
 	"CorePerfTests",
@@ -120,6 +122,7 @@
 	"services.usage",
 	"services.usb",
 	"Settings-core",
+	"SettingsGoogle",
 	"SettingsLib",
 	"SettingsProvider",
 	"SettingsProviderTest",
diff --git a/java/platform_bootclasspath.go b/java/platform_bootclasspath.go
index 02343ad..3f5c940 100644
--- a/java/platform_bootclasspath.go
+++ b/java/platform_bootclasspath.go
@@ -44,13 +44,9 @@
 	properties platformBootclasspathProperties
 
 	// The apex:module pairs obtained from the configured modules.
-	//
-	// Currently only for testing.
 	configuredModules []android.Module
 
 	// The apex:module pairs obtained from the fragments.
-	//
-	// Currently only for testing.
 	fragments []android.Module
 
 	// Path to the monolithic hiddenapi-flags.csv file.
@@ -280,7 +276,15 @@
 		return nil
 	}
 
-	monolithicInfo := b.createAndProvideMonolithicHiddenAPIInfo(ctx, fragments)
+	// Construct a list of ClasspathElement objects from the modules and fragments.
+	classpathElements := CreateClasspathElements(ctx, modules, fragments)
+
+	monolithicInfo := b.createAndProvideMonolithicHiddenAPIInfo(ctx, classpathElements)
+
+	// Extract the classes jars only from those libraries that do not have corresponding fragments as
+	// the fragments will have already provided the flags that are needed.
+	classesJars := monolithicInfo.ClassesJars
+
 	// Create the input to pass to ruleToGenerateHiddenAPIStubFlagsFile
 	input := newHiddenAPIFlagInput()
 
@@ -297,9 +301,6 @@
 	rule := ruleToGenerateHiddenAPIStubFlagsFile(ctx, stubFlags, bootDexJarByModule.bootDexJars(), input)
 	rule.Build("platform-bootclasspath-monolithic-hiddenapi-stub-flags", "monolithic hidden API stub flags")
 
-	// Extract the classes jars from the contents.
-	classesJars := extractClassesJarsFromModules(modules)
-
 	// Generate the annotation-flags.csv file from all the module annotations.
 	annotationFlags := android.PathForModuleOut(ctx, "hiddenapi-monolithic", "annotation-flags.csv")
 	buildRuleToGenerateAnnotationFlags(ctx, "monolithic hiddenapi flags", classesJars, stubFlags, annotationFlags)
@@ -329,7 +330,7 @@
 
 // createAndProvideMonolithicHiddenAPIInfo creates a MonolithicHiddenAPIInfo and provides it for
 // testing.
-func (b *platformBootclasspathModule) createAndProvideMonolithicHiddenAPIInfo(ctx android.ModuleContext, fragments []android.Module) MonolithicHiddenAPIInfo {
+func (b *platformBootclasspathModule) createAndProvideMonolithicHiddenAPIInfo(ctx android.ModuleContext, classpathElements ClasspathElements) MonolithicHiddenAPIInfo {
 	// Create a temporary input structure in which to collate information provided directly by this
 	// module, either through properties or direct dependencies.
 	temporaryInput := newHiddenAPIFlagInput()
@@ -339,7 +340,7 @@
 
 	// Create the monolithic info, by starting with the flag files specified on this and then merging
 	// in information from all the fragment dependencies of this.
-	monolithicInfo := newMonolithicHiddenAPIInfo(ctx, temporaryInput.FlagFilesByCategory, fragments)
+	monolithicInfo := newMonolithicHiddenAPIInfo(ctx, temporaryInput.FlagFilesByCategory, classpathElements)
 
 	// Store the information for testing.
 	ctx.SetProvider(MonolithicHiddenAPIInfoProvider, monolithicInfo)
diff --git a/java/platform_bootclasspath_test.go b/java/platform_bootclasspath_test.go
index 0318a07..87a6411 100644
--- a/java/platform_bootclasspath_test.go
+++ b/java/platform_bootclasspath_test.go
@@ -319,10 +319,9 @@
 	// creates the index.csv file.
 	platformBootclasspath := result.ModuleForTests("myplatform-bootclasspath", "android_common")
 	indexRule := platformBootclasspath.Rule("monolithic_hidden_API_index")
-	CheckHiddenAPIRuleInputs(t, `
-.intermediates/bar/android_common/javac/bar.jar
-.intermediates/foo-hiddenapi-annotations/android_common/javac/foo-hiddenapi-annotations.jar
-.intermediates/foo/android_common/javac/foo.jar
-`,
-		indexRule)
+	CheckHiddenAPIRuleInputs(t, "index", `
+			out/soong/.intermediates/bar/android_common/javac/bar.jar
+			out/soong/.intermediates/foo-hiddenapi-annotations/android_common/javac/foo-hiddenapi-annotations.jar
+			out/soong/.intermediates/foo/android_common/javac/foo.jar
+	`, indexRule)
 }
diff --git a/java/sdk_library.go b/java/sdk_library.go
index 9492729..41097ca 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -2144,7 +2144,7 @@
 
 			// Get the path of the dex implementation jar from the `deapexer` module.
 			di := ctx.OtherModuleProvider(deapexerModule, android.DeapexerProvider).(android.DeapexerInfo)
-			if dexOutputPath := di.PrebuiltExportPath(module.BaseModuleName(), ".dexjar"); dexOutputPath != nil {
+			if dexOutputPath := di.PrebuiltExportPath(apexRootRelativePathToJavaLib(module.BaseModuleName())); dexOutputPath != nil {
 				module.dexJarFile = dexOutputPath
 				module.initHiddenAPI(ctx, dexOutputPath, module.findScopePaths(apiScopePublic).stubsImplPath[0], nil)
 			} else {
@@ -2269,6 +2269,13 @@
 	}
 }
 
+var _ android.RequiredFilesFromPrebuiltApex = (*SdkLibraryImport)(nil)
+
+func (module *SdkLibraryImport) RequiredFilesFromPrebuiltApex(ctx android.BaseModuleContext) []string {
+	name := module.BaseModuleName()
+	return requiredFilesFromPrebuiltApexForImport(name)
+}
+
 //
 // java_sdk_library_xml
 //
diff --git a/java/systemserver_classpath_fragment.go b/java/systemserver_classpath_fragment.go
index c63a53f..a0decb7 100644
--- a/java/systemserver_classpath_fragment.go
+++ b/java/systemserver_classpath_fragment.go
@@ -64,6 +64,9 @@
 	ClasspathFragmentBase
 
 	properties systemServerClasspathFragmentProperties
+
+	// Collect the module directory for IDE info in java/jdeps.go.
+	modulePaths []string
 }
 
 func (s *SystemServerClasspathModule) ShouldSupportSdkVersion(ctx android.BaseModuleContext, sdkVersion android.ApiLevel) error {
@@ -93,6 +96,9 @@
 
 	classpathJars := configuredJarListToClasspathJars(ctx, s.configuredJars(ctx), s.classpathType)
 	s.classpathFragmentBase().generateClasspathProtoBuildActions(ctx, classpathJars)
+
+	// Collect the module directory for IDE info in java/jdeps.go.
+	s.modulePaths = append(s.modulePaths, ctx.ModuleDir())
 }
 
 func (s *SystemServerClasspathModule) configuredJars(ctx android.ModuleContext) android.ConfiguredJarList {
@@ -139,3 +145,9 @@
 		ctx.AddDependency(module, systemServerClasspathFragmentContentDepTag, name)
 	}
 }
+
+// Collect information for opening IDE project files in java/jdeps.go.
+func (s *SystemServerClasspathModule) IDEInfo(dpInfo *android.IdeInfo) {
+	dpInfo.Deps = append(dpInfo.Deps, s.properties.Contents...)
+	dpInfo.Paths = append(dpInfo.Paths, s.modulePaths...)
+}
diff --git a/java/testing.go b/java/testing.go
index 1fef337..7b452f7 100644
--- a/java/testing.go
+++ b/java/testing.go
@@ -17,6 +17,7 @@
 import (
 	"fmt"
 	"reflect"
+	"regexp"
 	"sort"
 	"strings"
 	"testing"
@@ -393,12 +394,20 @@
 	android.AssertDeepEquals(t, fmt.Sprintf("%s fragments", "platform-bootclasspath"), expected, pairs)
 }
 
-func CheckHiddenAPIRuleInputs(t *testing.T, expected string, hiddenAPIRule android.TestingBuildParams) {
+func CheckHiddenAPIRuleInputs(t *testing.T, message string, expected string, hiddenAPIRule android.TestingBuildParams) {
 	t.Helper()
-	actual := strings.TrimSpace(strings.Join(android.NormalizePathsForTesting(hiddenAPIRule.Implicits), "\n"))
-	expected = strings.TrimSpace(expected)
+	inputs := android.Paths{}
+	if hiddenAPIRule.Input != nil {
+		inputs = append(inputs, hiddenAPIRule.Input)
+	}
+	inputs = append(inputs, hiddenAPIRule.Inputs...)
+	inputs = append(inputs, hiddenAPIRule.Implicits...)
+	inputs = android.SortedUniquePaths(inputs)
+	actual := strings.TrimSpace(strings.Join(inputs.RelativeToTop().Strings(), "\n"))
+	re := regexp.MustCompile(`\n\s+`)
+	expected = strings.TrimSpace(re.ReplaceAllString(expected, "\n"))
 	if actual != expected {
-		t.Errorf("Expected hiddenapi rule inputs:\n%s\nactual inputs:\n%s", expected, actual)
+		t.Errorf("Expected hiddenapi rule inputs - %s:\n%s\nactual inputs:\n%s", message, expected, actual)
 	}
 }
 
diff --git a/sysprop/sysprop_library.go b/sysprop/sysprop_library.go
index f1c2d0d..a29d4c3 100644
--- a/sysprop/sysprop_library.go
+++ b/sysprop/sysprop_library.go
@@ -145,6 +145,9 @@
 	// If set to true, allow this module to be dexed and installed on devices.
 	Installable *bool
 
+	// Make this module available when building for ramdisk
+	Ramdisk_available *bool
+
 	// Make this module available when building for recovery
 	Recovery_available *bool
 
@@ -396,6 +399,7 @@
 	Recovery_available *bool
 	Vendor_available   *bool
 	Product_available  *bool
+	Ramdisk_available  *bool
 	Host_supported     *bool
 	Apex_available     []string
 	Min_sdk_version    *string
@@ -475,6 +479,7 @@
 	ccProps.Recovery_available = m.properties.Recovery_available
 	ccProps.Vendor_available = m.properties.Vendor_available
 	ccProps.Product_available = m.properties.Product_available
+	ccProps.Ramdisk_available = m.properties.Ramdisk_available
 	ccProps.Host_supported = m.properties.Host_supported
 	ccProps.Apex_available = m.ApexProperties.Apex_available
 	ccProps.Min_sdk_version = m.properties.Cpp.Min_sdk_version