diff --git a/java/classpath_fragment.go b/java/classpath_fragment.go
index adbe490..d497460 100644
--- a/java/classpath_fragment.go
+++ b/java/classpath_fragment.go
@@ -17,6 +17,9 @@
 package java
 
 import (
+	"fmt"
+	"strings"
+
 	"android/soong/android"
 )
 
@@ -47,21 +50,102 @@
 type classpathFragment interface {
 	android.Module
 
-	classpathFragmentBase() *classpathFragmentBase
+	classpathFragmentBase() *ClasspathFragmentBase
 }
 
-// classpathFragmentBase is meant to be embedded in any module types that implement classpathFragment;
+// ClasspathFragmentBase is meant to be embedded in any module types that implement classpathFragment;
 // such modules are expected to call initClasspathFragment().
-type classpathFragmentBase struct {
+type ClasspathFragmentBase struct {
 	properties classpathFragmentProperties
 
-	classpathType classpathType
-
 	outputFilepath android.OutputPath
+	installDirPath android.InstallPath
 }
 
-// Initializes classpathFragmentBase struct. Must be called by all modules that include classpathFragmentBase.
+func (c *ClasspathFragmentBase) classpathFragmentBase() *ClasspathFragmentBase {
+	return c
+}
+
+// Initializes ClasspathFragmentBase struct. Must be called by all modules that include ClasspathFragmentBase.
 func initClasspathFragment(c classpathFragment) {
 	base := c.classpathFragmentBase()
 	c.AddProperties(&base.properties)
 }
+
+// Matches definition of Jar in packages/modules/SdkExtensions/proto/classpaths.proto
+type classpathJar struct {
+	path      string
+	classpath classpathType
+	// TODO(satayev): propagate min/max sdk versions for the jars
+	minSdkVersion int32
+	maxSdkVersion int32
+}
+
+func (c *ClasspathFragmentBase) generateAndroidBuildActions(ctx android.ModuleContext) {
+	outputFilename := ctx.ModuleName() + ".pb"
+	c.outputFilepath = android.PathForModuleOut(ctx, outputFilename).OutputPath
+	c.installDirPath = android.PathForModuleInstall(ctx, "etc", "classpaths")
+
+	var jars []classpathJar
+	jars = appendClasspathJar(jars, BOOTCLASSPATH, defaultBootclasspath(ctx)...)
+	jars = appendClasspathJar(jars, DEX2OATBOOTCLASSPATH, defaultBootImageConfig(ctx).getAnyAndroidVariant().dexLocationsDeps...)
+	jars = appendClasspathJar(jars, SYSTEMSERVERCLASSPATH, systemServerClasspath(ctx)...)
+
+	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.Build("classpath_fragment", "Compiling "+c.outputFilepath.String())
+}
+
+func writeClasspathsJson(ctx android.ModuleContext, output android.WritablePath, jars []classpathJar) {
+	var content strings.Builder
+	fmt.Fprintf(&content, "{\n")
+	fmt.Fprintf(&content, "\"jars\": [\n")
+	for idx, jar := range jars {
+		fmt.Fprintf(&content, "{\n")
+
+		fmt.Fprintf(&content, "\"relativePath\": \"%s\",\n", jar.path)
+		fmt.Fprintf(&content, "\"classpath\": \"%s\"\n", jar.classpath)
+
+		if idx < len(jars)-1 {
+			fmt.Fprintf(&content, "},\n")
+		} else {
+			fmt.Fprintf(&content, "}\n")
+		}
+	}
+	fmt.Fprintf(&content, "]\n")
+	fmt.Fprintf(&content, "}\n")
+	android.WriteFileRule(ctx, output, content.String())
+}
+
+func appendClasspathJar(slice []classpathJar, classpathType classpathType, paths ...string) (result []classpathJar) {
+	result = append(result, slice...)
+	for _, path := range paths {
+		result = append(result, classpathJar{
+			path:      path,
+			classpath: classpathType,
+		})
+	}
+	return
+}
+
+func (c *ClasspathFragmentBase) getAndroidMkEntries() []android.AndroidMkEntries {
+	return []android.AndroidMkEntries{android.AndroidMkEntries{
+		Class:      "ETC",
+		OutputFile: android.OptionalPathForPath(c.outputFilepath),
+		ExtraEntries: []android.AndroidMkExtraEntriesFunc{
+			func(ctx android.AndroidMkExtraEntriesContext, entries *android.AndroidMkEntries) {
+				entries.SetString("LOCAL_MODULE_PATH", c.installDirPath.ToMakePath().String())
+				entries.SetString("LOCAL_INSTALLED_MODULE_STEM", c.outputFilepath.Base())
+			},
+		},
+	}}
+}
diff --git a/java/dexpreopt_config.go b/java/dexpreopt_config.go
index 64b2656..656f5ef 100644
--- a/java/dexpreopt_config.go
+++ b/java/dexpreopt_config.go
@@ -26,7 +26,7 @@
 // systemServerClasspath returns the on-device locations of the modules in the system server classpath.  It is computed
 // once the first time it is called for any ctx.Config(), and returns the same slice for all future calls with the same
 // ctx.Config().
-func systemServerClasspath(ctx android.MakeVarsContext) []string {
+func systemServerClasspath(ctx android.PathContext) []string {
 	return ctx.Config().OnceStringSlice(systemServerClasspathKey, func() []string {
 		global := dexpreopt.GetGlobalConfig(ctx)
 		var systemServerClasspathLocations []string
diff --git a/java/platform_bootclasspath.go b/java/platform_bootclasspath.go
index d98ce67..6f242a1 100644
--- a/java/platform_bootclasspath.go
+++ b/java/platform_bootclasspath.go
@@ -59,6 +59,7 @@
 
 type platformBootclasspathModule struct {
 	android.ModuleBase
+	ClasspathFragmentBase
 
 	properties platformBootclasspathProperties
 
@@ -105,22 +106,23 @@
 func platformBootclasspathFactory() android.Module {
 	m := &platformBootclasspathModule{}
 	m.AddProperties(&m.properties)
+	// TODO(satayev): split systemserver and apex jars into separate configs.
+	initClasspathFragment(m)
 	android.InitAndroidArchModule(m, android.DeviceSupported, android.MultilibCommon)
 	return m
 }
 
 var _ android.OutputFileProducer = (*platformBootclasspathModule)(nil)
 
-// A minimal AndroidMkEntries is needed in order to support the dists property.
-func (b *platformBootclasspathModule) AndroidMkEntries() []android.AndroidMkEntries {
-	return []android.AndroidMkEntries{
-		{
-			Class: "FAKE",
-			// Need at least one output file in order for this to take effect.
-			OutputFile: android.OptionalPathForPath(b.hiddenAPIFlagsCSV),
-			Include:    "$(BUILD_PHONY_PACKAGE)",
-		},
-	}
+func (b *platformBootclasspathModule) AndroidMkEntries() (entries []android.AndroidMkEntries) {
+	entries = append(entries, android.AndroidMkEntries{
+		Class: "FAKE",
+		// Need at least one output file in order for this to take effect.
+		OutputFile: android.OptionalPathForPath(b.hiddenAPIFlagsCSV),
+		Include:    "$(BUILD_PHONY_PACKAGE)",
+	})
+	entries = append(entries, b.classpathFragmentBase().getAndroidMkEntries()...)
+	return
 }
 
 // Make the hidden API files available from the platform-bootclasspath module.
@@ -222,6 +224,8 @@
 }
 
 func (b *platformBootclasspathModule) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	b.classpathFragmentBase().generateAndroidBuildActions(ctx)
+
 	ctx.VisitDirectDepsIf(isActiveModule, func(module android.Module) {
 		tag := ctx.OtherModuleDependencyTag(module)
 		if tag == platformBootclasspathModuleDepTag {
diff --git a/java/platform_bootclasspath_test.go b/java/platform_bootclasspath_test.go
index c740911..26587c7 100644
--- a/java/platform_bootclasspath_test.go
+++ b/java/platform_bootclasspath_test.go
@@ -132,6 +132,89 @@
 	})
 }
 
+func TestPlatformBootclasspathVariant(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		prepareForTestWithPlatformBootclasspath,
+		android.FixtureWithRootAndroidBp(`
+			platform_bootclasspath {
+				name: "platform-bootclasspath",
+			}
+		`),
+	).RunTest(t)
+
+	variants := result.ModuleVariantsForTests("platform-bootclasspath")
+	android.AssertIntEquals(t, "expect 1 variant", 1, len(variants))
+}
+
+func TestPlatformBootclasspath_ClasspathFragmentPaths(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		prepareForTestWithPlatformBootclasspath,
+		android.FixtureWithRootAndroidBp(`
+			platform_bootclasspath {
+				name: "platform-bootclasspath",
+			}
+		`),
+	).RunTest(t)
+
+	p := result.Module("platform-bootclasspath", "android_common").(*platformBootclasspathModule)
+	android.AssertStringEquals(t, "output filepath", p.Name()+".pb", p.ClasspathFragmentBase.outputFilepath.Base())
+	android.AssertPathRelativeToTopEquals(t, "install filepath", "out/soong/target/product/test_device/system/etc/classpaths", p.ClasspathFragmentBase.installDirPath)
+}
+
+func TestPlatformBootclasspathModule_AndroidMkEntries(t *testing.T) {
+	preparer := android.GroupFixturePreparers(
+		prepareForTestWithPlatformBootclasspath,
+		android.FixtureWithRootAndroidBp(`
+			platform_bootclasspath {
+				name: "platform-bootclasspath",
+			}
+		`),
+	)
+
+	t.Run("AndroidMkEntries", func(t *testing.T) {
+		result := preparer.RunTest(t)
+
+		p := result.Module("platform-bootclasspath", "android_common").(*platformBootclasspathModule)
+
+		entries := android.AndroidMkEntriesForTest(t, result.TestContext, p)
+		android.AssertIntEquals(t, "AndroidMkEntries count", 2, len(entries))
+	})
+
+	t.Run("hiddenapi-flags-entry", func(t *testing.T) {
+		result := preparer.RunTest(t)
+
+		p := result.Module("platform-bootclasspath", "android_common").(*platformBootclasspathModule)
+
+		entries := android.AndroidMkEntriesForTest(t, result.TestContext, p)
+		got := entries[0].OutputFile
+		android.AssertBoolEquals(t, "valid output path", true, got.Valid())
+		android.AssertSame(t, "output filepath", p.hiddenAPIFlagsCSV, got.Path())
+	})
+
+	t.Run("classpath-fragment-entry", func(t *testing.T) {
+		result := preparer.RunTest(t)
+
+		want := map[string][]string{
+			"LOCAL_MODULE":                {"platform-bootclasspath"},
+			"LOCAL_MODULE_CLASS":          {"ETC"},
+			"LOCAL_INSTALLED_MODULE_STEM": {"platform-bootclasspath.pb"},
+			// Output and Install paths are tested separately in TestPlatformBootclasspath_ClasspathFragmentPaths
+		}
+
+		p := result.Module("platform-bootclasspath", "android_common").(*platformBootclasspathModule)
+
+		entries := android.AndroidMkEntriesForTest(t, result.TestContext, p)
+		got := entries[1]
+		for k, expectedValue := range want {
+			if value, ok := got.EntryMap[k]; ok {
+				android.AssertDeepEquals(t, k, expectedValue, value)
+			} else {
+				t.Errorf("No %s defined, saw %q", k, got.EntryMap)
+			}
+		}
+	})
+}
+
 func TestPlatformBootclasspath_Dist(t *testing.T) {
 	result := android.GroupFixturePreparers(
 		prepareForTestWithPlatformBootclasspath,