diff --git a/android/config_test.go b/android/config_test.go
index ca7c7f8..7732168 100644
--- a/android/config_test.go
+++ b/android/config_test.go
@@ -150,12 +150,7 @@
 
 	for _, tc := range testCases {
 		fixture := GroupFixturePreparers(
-			FixtureModifyProductVariables(func(vars FixtureProductVariables) {
-				if vars.BuildFlags == nil {
-					vars.BuildFlags = make(map[string]string)
-				}
-				vars.BuildFlags["RELEASE_ACONFIG_EXTRA_RELEASE_CONFIGS"] = tc.flag
-			}),
+			PrepareForTestWithBuildFlag("RELEASE_ACONFIG_EXTRA_RELEASE_CONFIGS", tc.flag),
 		)
 		actual := fixture.RunTest(t).Config.ReleaseAconfigExtraReleaseConfigs()
 		AssertArrayString(t, tc.name, tc.expected, actual)
diff --git a/android/prebuilt_test.go b/android/prebuilt_test.go
index 6e4fc0c..5e4af0b 100644
--- a/android/prebuilt_test.go
+++ b/android/prebuilt_test.go
@@ -574,11 +574,7 @@
 
 func TestPrebuiltErrorCannotListBothSourceAndPrebuiltInContributions(t *testing.T) {
 	selectMainlineModuleContritbutions := GroupFixturePreparers(
-		FixtureModifyProductVariables(func(variables FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "my_apex_contributions",
-			}
-		}),
+		PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "my_apex_contributions"),
 	)
 	testPrebuiltErrorWithFixture(t, `Found duplicate variations of the same module in apex_contributions: foo and prebuilt_foo. Please remove one of these`, `
 		source {
diff --git a/android/testing.go b/android/testing.go
index dae787b..e3853b8 100644
--- a/android/testing.go
+++ b/android/testing.go
@@ -174,6 +174,16 @@
 	config.TestAllowNonExistentPaths = false
 })
 
+// PrepareForTestWithBuildFlag returns a FixturePreparer that sets the given flag to the given value.
+func PrepareForTestWithBuildFlag(flag, value string) FixturePreparer {
+	return FixtureModifyProductVariables(func(variables FixtureProductVariables) {
+		if variables.BuildFlags == nil {
+			variables.BuildFlags = make(map[string]string)
+		}
+		variables.BuildFlags[flag] = value
+	})
+}
+
 func NewTestArchContext(config Config) *TestContext {
 	ctx := NewTestContext(config)
 	ctx.preDeps = append(ctx.preDeps, registerArchMutator)
diff --git a/apex/apex_test.go b/apex/apex_test.go
index 852f5fb..d6c8a8a 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -11299,11 +11299,7 @@
 				fs["platform/Test.java"] = nil
 			}),
 
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": tc.selectedApexContributions,
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", tc.selectedApexContributions),
 		)
 		ctx := testDexpreoptWithApexes(t, bp, "", preparer, fragment)
 		checkBootDexJarPath(t, ctx, "framework-foo", tc.expectedBootJar)
@@ -11442,11 +11438,7 @@
 			android.FixtureMergeMockFs(map[string][]byte{
 				"system/sepolicy/apex/com.android.foo-file_contexts": nil,
 			}),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": tc.selectedApexContributions,
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", tc.selectedApexContributions),
 		)
 		if tc.expectedError != "" {
 			preparer = preparer.ExtendWithErrorHandler(android.FixtureExpectsOneErrorPattern(tc.expectedError))
@@ -11562,11 +11554,7 @@
 			android.FixtureMergeMockFs(map[string][]byte{
 				"system/sepolicy/apex/com.android.adservices-file_contexts": nil,
 			}),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": tc.selectedApexContributions,
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", tc.selectedApexContributions),
 		)
 		ctx := testApex(t, bp, preparer)
 
diff --git a/apex/bootclasspath_fragment_test.go b/apex/bootclasspath_fragment_test.go
index 533f937..f8c823e 100644
--- a/apex/bootclasspath_fragment_test.go
+++ b/apex/bootclasspath_fragment_test.go
@@ -53,11 +53,7 @@
 		java.FixtureConfigureBootJars("com.android.art:baz", "com.android.art:quuz"),
 		java.FixtureConfigureApexBootJars("someapex:foo", "someapex:bar"),
 		prepareForTestWithArtApex,
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 		java.PrepareForTestWithJavaSdkLibraryFiles,
 		java.FixtureWithLastReleaseApis("foo", "baz"),
 	).RunTestWithBp(t, `
@@ -731,11 +727,7 @@
 
 		java.PrepareForTestWithJavaSdkLibraryFiles,
 		java.FixtureWithLastReleaseApis("foo", "quuz"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		apex {
 			name: "com.android.art",
diff --git a/apex/dexpreopt_bootjars_test.go b/apex/dexpreopt_bootjars_test.go
index 7a17f50..95db37d 100644
--- a/apex/dexpreopt_bootjars_test.go
+++ b/apex/dexpreopt_bootjars_test.go
@@ -399,11 +399,7 @@
 			java.FixtureConfigureBootJars("com.android.art:core-oj"),
 			PrepareForTestWithApexBuildComponents,
 			prepareForTestWithArtApex,
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ART": tc.selectedArtApexContributions,
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ART", tc.selectedArtApexContributions),
 		).RunTestWithBp(t, bp)
 
 		dexBootJars := result.ModuleForTests("dex_bootjars", "android_common")
diff --git a/apex/platform_bootclasspath_test.go b/apex/platform_bootclasspath_test.go
index 4a20cf0..645eebb 100644
--- a/apex/platform_bootclasspath_test.go
+++ b/apex/platform_bootclasspath_test.go
@@ -254,11 +254,7 @@
 		java.FixtureWithLastReleaseApis("foo"),
 		java.PrepareForTestWithDexpreopt,
 		dexpreopt.FixtureDisableDexpreoptBootImages(false),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		apex {
 			name: "com.android.art",
@@ -429,10 +425,9 @@
 		java.PrepareForTestWithJavaSdkLibraryFiles,
 		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
 			variables.Always_use_prebuilt_sdks = proptools.BoolPtr(true)
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
 		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
+
 		java.FixtureWithPrebuiltApis(map[string][]string{
 			"current": {},
 			"30":      {"foo"},
@@ -935,11 +930,7 @@
 			PrepareForTestWithApexBuildComponents,
 			prepareForTestWithMyapex,
 			java.FixtureConfigureApexBootJars(tc.configuredBootJars...),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ART": "my_apex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ART", "my_apex_contributions"),
 		)
 		if tc.errorExpected {
 			fixture = fixture.ExtendWithErrorHandler(
diff --git a/cc/cc_test.go b/cc/cc_test.go
index b1c0945..7372fff 100644
--- a/cc/cc_test.go
+++ b/cc/cc_test.go
@@ -3194,12 +3194,7 @@
 
 	ctx = android.GroupFixturePreparers(
 		prepareForCcTest,
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			if variables.BuildFlags == nil {
-				variables.BuildFlags = make(map[string]string)
-			}
-			variables.BuildFlags["RELEASE_BOARD_API_LEVEL_FROZEN"] = "true"
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_BOARD_API_LEVEL_FROZEN", "true"),
 	).RunTestWithBp(t, bp)
 	testSdkVersionFlag("libfoo", "30")
 	testSdkVersionFlag("libbar", "29")
diff --git a/cc/prebuilt_test.go b/cc/prebuilt_test.go
index 86e6af9..acbbabc 100644
--- a/cc/prebuilt_test.go
+++ b/cc/prebuilt_test.go
@@ -476,11 +476,7 @@
 			android.FixtureRegisterWithContext(func(ctx android.RegistrationContext) {
 				android.RegisterApexContributionsBuildComponents(ctx)
 			}),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 		)
 		ctx := testPrebuilt(t, fmt.Sprintf(bp, tc.selectedDependencyName), map[string][]byte{
 			"libbar.so": nil,
@@ -574,11 +570,7 @@
 			android.FixtureRegisterWithContext(func(ctx android.RegistrationContext) {
 				android.RegisterApexContributionsBuildComponents(ctx)
 			}),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 		)
 		if tc.expectedErr != "" {
 			preparer = preparer.ExtendWithErrorHandler(android.FixtureExpectsAtLeastOneErrorMatchingPattern(tc.expectedErr))
@@ -638,11 +630,7 @@
 		android.FixtureRegisterWithContext(func(ctx android.RegistrationContext) {
 			android.RegisterApexContributionsBuildComponents(ctx)
 		}),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 	)
 	ctx := testPrebuilt(t, bp, map[string][]byte{
 		"libbar.so": nil,
diff --git a/java/base.go b/java/base.go
index f820629..8a4c64d 100644
--- a/java/base.go
+++ b/java/base.go
@@ -2027,16 +2027,20 @@
 
 // Collect information for opening IDE project files in java/jdeps.go.
 func (j *Module) IDEInfo(dpInfo *android.IdeInfo) {
-	dpInfo.Deps = append(dpInfo.Deps, j.CompilerDeps()...)
-	dpInfo.Srcs = append(dpInfo.Srcs, j.expandIDEInfoCompiledSrcs...)
-	dpInfo.SrcJars = append(dpInfo.SrcJars, j.compiledSrcJars.Strings()...)
-	dpInfo.Aidl_include_dirs = append(dpInfo.Aidl_include_dirs, j.deviceProperties.Aidl.Include_dirs...)
+	// jarjar rules will repackage the sources. To prevent misleading results, IdeInfo should contain the
+	// repackaged jar instead of the input sources.
 	if j.expandJarjarRules != nil {
 		dpInfo.Jarjar_rules = append(dpInfo.Jarjar_rules, j.expandJarjarRules.String())
+		dpInfo.Jars = append(dpInfo.Jars, j.headerJarFile.String())
+	} else {
+		dpInfo.Srcs = append(dpInfo.Srcs, j.expandIDEInfoCompiledSrcs...)
+		dpInfo.SrcJars = append(dpInfo.SrcJars, j.compiledSrcJars.Strings()...)
+		dpInfo.SrcJars = append(dpInfo.SrcJars, j.annoSrcJars.Strings()...)
 	}
+	dpInfo.Deps = append(dpInfo.Deps, j.CompilerDeps()...)
+	dpInfo.Aidl_include_dirs = append(dpInfo.Aidl_include_dirs, j.deviceProperties.Aidl.Include_dirs...)
 	dpInfo.Static_libs = append(dpInfo.Static_libs, j.properties.Static_libs...)
 	dpInfo.Libs = append(dpInfo.Libs, j.properties.Libs...)
-	dpInfo.SrcJars = append(dpInfo.SrcJars, j.annoSrcJars.Strings()...)
 }
 
 func (j *Module) CompilerDeps() []string {
@@ -2374,16 +2378,24 @@
 			case bootClasspathTag:
 				// If a system modules dependency has been added to the bootclasspath
 				// then add its libs to the bootclasspath.
-				sm := module.(SystemModulesProvider)
-				deps.bootClasspath = append(deps.bootClasspath, sm.HeaderJars()...)
+				if sm, ok := android.OtherModuleProvider(ctx, module, SystemModulesProvider); ok {
+					depHeaderJars := sm.HeaderJars
+					deps.bootClasspath = append(deps.bootClasspath, depHeaderJars...)
+				} else {
+					ctx.PropertyErrorf("boot classpath dependency %q does not provide SystemModulesProvider",
+						ctx.OtherModuleName(module))
+				}
 
 			case systemModulesTag:
 				if deps.systemModules != nil {
 					panic("Found two system module dependencies")
 				}
-				sm := module.(SystemModulesProvider)
-				outputDir, outputDeps := sm.OutputDirAndDeps()
-				deps.systemModules = &systemModules{outputDir, outputDeps}
+				if sm, ok := android.OtherModuleProvider(ctx, module, SystemModulesProvider); ok {
+					deps.systemModules = &systemModules{sm.OutputDir, sm.OutputDirDeps}
+				} else {
+					ctx.PropertyErrorf("system modules dependency %q does not provide SystemModulesProvider",
+						ctx.OtherModuleName(module))
+				}
 
 			case instrumentationForTag:
 				ctx.PropertyErrorf("instrumentation_for", "dependency %q of type %q does not provide JavaInfo so is unsuitable for use with this property", ctx.OtherModuleName(module), ctx.OtherModuleType(module))
diff --git a/java/bootclasspath_fragment_test.go b/java/bootclasspath_fragment_test.go
index 8bc0a7e..d72417a 100644
--- a/java/bootclasspath_fragment_test.go
+++ b/java/bootclasspath_fragment_test.go
@@ -222,11 +222,7 @@
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("mysdklibrary", "myothersdklibrary", "mycoreplatform"),
 		FixtureConfigureApexBootJars("someapex:mysdklibrary"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		bootclasspath_fragment {
 			name: "myfragment",
diff --git a/java/droiddoc.go b/java/droiddoc.go
index 730f236..f81c5ba 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -365,10 +365,10 @@
 		case bootClasspathTag:
 			if dep, ok := android.OtherModuleProvider(ctx, module, JavaInfoProvider); ok {
 				deps.bootClasspath = append(deps.bootClasspath, dep.ImplementationJars...)
-			} else if sm, ok := module.(SystemModulesProvider); ok {
+			} else if sm, ok := android.OtherModuleProvider(ctx, module, SystemModulesProvider); ok {
 				// A system modules dependency has been added to the bootclasspath
 				// so add its libs to the bootclasspath.
-				deps.bootClasspath = append(deps.bootClasspath, sm.HeaderJars()...)
+				deps.bootClasspath = append(deps.bootClasspath, sm.HeaderJars...)
 			} else {
 				panic(fmt.Errorf("unknown dependency %q for %q", otherName, ctx.ModuleName()))
 			}
@@ -396,9 +396,12 @@
 			if deps.systemModules != nil {
 				panic("Found two system module dependencies")
 			}
-			sm := module.(SystemModulesProvider)
-			outputDir, outputDeps := sm.OutputDirAndDeps()
-			deps.systemModules = &systemModules{outputDir, outputDeps}
+			if sm, ok := android.OtherModuleProvider(ctx, module, SystemModulesProvider); ok {
+				deps.systemModules = &systemModules{sm.OutputDir, sm.OutputDirDeps}
+			} else {
+				ctx.PropertyErrorf("boot classpath dependency %q does not provide SystemModulesProvider",
+					ctx.OtherModuleName(module))
+			}
 		case aconfigDeclarationTag:
 			if dep, ok := android.OtherModuleProvider(ctx, module, android.AconfigDeclarationsProviderKey); ok {
 				deps.aconfigProtoFiles = append(deps.aconfigProtoFiles, dep.IntermediateCacheOutputPath)
diff --git a/java/droidstubs_test.go b/java/droidstubs_test.go
index 6a14f36..1e8362c 100644
--- a/java/droidstubs_test.go
+++ b/java/droidstubs_test.go
@@ -421,11 +421,9 @@
 	result := android.GroupFixturePreparers(
 		prepareForJavaTest,
 		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
 			variables.ExportRuntimeApis = proptools.BoolPtr(true)
 		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 		android.FixtureMergeMockFs(map[string][]byte{
 			"a/A.java":      nil,
 			"a/current.txt": nil,
diff --git a/java/hiddenapi_singleton_test.go b/java/hiddenapi_singleton_test.go
index 6229797..afe8b4c 100644
--- a/java/hiddenapi_singleton_test.go
+++ b/java/hiddenapi_singleton_test.go
@@ -203,10 +203,8 @@
 				FixtureConfigureBootJars("platform:foo"),
 				android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
 					variables.Always_use_prebuilt_sdks = proptools.BoolPtr(tc.unbundledBuild)
-					variables.BuildFlags = map[string]string{
-						"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-					}
 				}),
+				android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 			).RunTestWithBp(t, `
 		java_library {
 			name: "foo",
diff --git a/java/java.go b/java/java.go
index be3f90b..126d8f3 100644
--- a/java/java.go
+++ b/java/java.go
@@ -2261,8 +2261,9 @@
 				staticLibs = append(staticLibs, provider.HeaderJars...)
 			}
 		case systemModulesTag:
-			module := dep.(SystemModulesProvider)
-			systemModulesPaths = append(systemModulesPaths, module.HeaderJars()...)
+			if sm, ok := android.OtherModuleProvider(ctx, dep, SystemModulesProvider); ok {
+				systemModulesPaths = append(systemModulesPaths, sm.HeaderJars...)
+			}
 		case metalavaCurrentApiTimestampTag:
 			if currentApiTimestampProvider, ok := dep.(currentApiTimestampProvider); ok {
 				al.validationPaths = append(al.validationPaths, currentApiTimestampProvider.CurrentApiTimestamp())
diff --git a/java/java_test.go b/java/java_test.go
index 2d4fca2..86bfe9f 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -2634,11 +2634,7 @@
 	for _, tc := range testCases {
 		ctx := android.GroupFixturePreparers(
 			prepareForJavaTest,
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 		).RunTestWithBp(t, fmt.Sprintf(bp, tc.selectedDependencyName))
 
 		// check that rdep gets the correct variation of dep
@@ -2708,11 +2704,7 @@
 		ctx := android.GroupFixturePreparers(
 			prepareForJavaTest,
 			PrepareForTestWithPlatformCompatConfig,
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 		).RunTestWithBp(t, fmt.Sprintf(bp, tc.selectedDependencyName))
 
 		mergedGlobalConfig := ctx.SingletonForTests("platform_compat_config_singleton").Output("compat_config/merged_compat_config.xml")
diff --git a/java/jdeps_test.go b/java/jdeps_test.go
index 47bfac1..ff54da9 100644
--- a/java/jdeps_test.go
+++ b/java/jdeps_test.go
@@ -91,16 +91,23 @@
 	}
 }
 
-func TestCollectJavaLibraryPropertiesAddJarjarRules(t *testing.T) {
-	expected := "Jarjar_rules.txt"
-	module := LibraryFactory().(*Library)
-	module.expandJarjarRules = android.PathForTesting(expected)
+func TestCollectJavaLibraryWithJarJarRules(t *testing.T) {
+	ctx, _ := testJava(t,
+		`
+		java_library {
+			name: "javalib",
+			srcs: ["foo.java"],
+			jarjar_rules: "jarjar_rules.txt",
+		}
+	`)
+	module := ctx.ModuleForTests("javalib", "android_common").Module().(*Library)
 	dpInfo := &android.IdeInfo{}
 
 	module.IDEInfo(dpInfo)
-
-	if dpInfo.Jarjar_rules[0] != expected {
-		t.Errorf("Library.IDEInfo() Jarjar_rules = %v, want %v", dpInfo.Jarjar_rules[0], expected)
+	android.AssertBoolEquals(t, "IdeInfo.Srcs of repackaged library should be empty", true, len(dpInfo.Srcs) == 0)
+	android.AssertStringEquals(t, "IdeInfo.Jar_rules of repackaged library should not be empty", "jarjar_rules.txt", dpInfo.Jarjar_rules[0])
+	if !android.SubstringInList(dpInfo.Jars, "soong/.intermediates/javalib/android_common/jarjar/turbine/javalib.jar") {
+		t.Errorf("IdeInfo.Jars of repackaged library should contain the output of jarjar-ing. All outputs: %v\n", dpInfo.Jars)
 	}
 }
 
diff --git a/java/sdk_library.go b/java/sdk_library.go
index a8cc1b8..4f95a99 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -3602,3 +3602,19 @@
 		propertySet.AddProperty("doctag_files", dests)
 	}
 }
+
+// TODO(b/358613520): This can be removed when modules are no longer allowed to depend on the top-level library.
+func (s *SdkLibrary) IDEInfo(dpInfo *android.IdeInfo) {
+	s.Library.IDEInfo(dpInfo)
+	if s.implLibraryModule != nil {
+		dpInfo.Deps = append(dpInfo.Deps, s.implLibraryModule.Name())
+	} else {
+		// This java_sdk_library does not have an implementation (it sets `api_only` to true).
+		// Examples of this are `art.module.intra.core.api` (IntraCore api surface).
+		// Return the "public" stubs for these.
+		stubPaths := s.findClosestScopePath(apiScopePublic)
+		if len(stubPaths.stubsHeaderPath) > 0 {
+			dpInfo.Jars = append(dpInfo.Jars, stubPaths.stubsHeaderPath[0].String())
+		}
+	}
+}
diff --git a/java/sdk_library_test.go b/java/sdk_library_test.go
index 911e8b1..368eca7 100644
--- a/java/sdk_library_test.go
+++ b/java/sdk_library_test.go
@@ -35,11 +35,7 @@
 			"29": {"foo"},
 			"30": {"bar", "barney", "baz", "betty", "foo", "fred", "quuz", "wilma"},
 		}),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		droiddoc_exported_dir {
 			name: "droiddoc-templates-sdk",
@@ -537,11 +533,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib",
@@ -934,11 +926,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib",
@@ -987,11 +975,7 @@
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
 		preparer,
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib",
@@ -1183,11 +1167,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib.source_preferred_using_legacy_flags", "sdklib.prebuilt_preferred_using_legacy_flags"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "my_mainline_module_contributions",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "my_mainline_module_contributions"),
 	).RunTestWithBp(t, bp)
 
 	// Make sure that rdeps get the correct source vs prebuilt based on mainline_module_contributions
@@ -1369,11 +1349,7 @@
 			"sdklib_group_foo",
 			"sdklib_owner_foo",
 			"foo"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib_no_group",
@@ -1785,12 +1761,8 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				// We can use any of the apex contribution build flags from build/soong/android/config.go#mainlineApexContributionBuildFlags here
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "my_mainline_module_contributions",
-			}
-		}),
+		// We can use any of the apex contribution build flags from build/soong/android/config.go#mainlineApexContributionBuildFlags here
+		android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "my_mainline_module_contributions"),
 	)
 
 	result := fixture.RunTestWithBp(t, bp)
@@ -1873,11 +1845,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib", "sdklib.v1", "sdklib.v2"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "my_mainline_module_contributions",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "my_mainline_module_contributions"),
 	)
 
 	for _, tc := range testCases {
diff --git a/java/system_modules.go b/java/system_modules.go
index 48b33ba..5b00079 100644
--- a/java/system_modules.go
+++ b/java/system_modules.go
@@ -120,14 +120,16 @@
 	return module
 }
 
-type SystemModulesProvider interface {
-	HeaderJars() android.Paths
-	OutputDirAndDeps() (android.Path, android.Paths)
+type SystemModulesProviderInfo struct {
+	// The aggregated header jars from all jars specified in the libs property.
+	// Used when system module is added as a dependency to bootclasspath.
+	HeaderJars android.Paths
+
+	OutputDir     android.Path
+	OutputDirDeps android.Paths
 }
 
-var _ SystemModulesProvider = (*SystemModules)(nil)
-
-var _ SystemModulesProvider = (*systemModulesImport)(nil)
+var SystemModulesProvider = blueprint.NewProvider[*SystemModulesProviderInfo]()
 
 type SystemModules struct {
 	android.ModuleBase
@@ -135,9 +137,6 @@
 
 	properties SystemModulesProperties
 
-	// The aggregated header jars from all jars specified in the libs property.
-	// Used when system module is added as a dependency to bootclasspath.
-	headerJars android.Paths
 	outputDir  android.Path
 	outputDeps android.Paths
 }
@@ -147,17 +146,6 @@
 	Libs []string
 }
 
-func (system *SystemModules) HeaderJars() android.Paths {
-	return system.headerJars
-}
-
-func (system *SystemModules) OutputDirAndDeps() (android.Path, android.Paths) {
-	if system.outputDir == nil || len(system.outputDeps) == 0 {
-		panic("Missing directory for system module dependency")
-	}
-	return system.outputDir, system.outputDeps
-}
-
 func (system *SystemModules) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	var jars android.Paths
 
@@ -167,9 +155,13 @@
 		}
 	})
 
-	system.headerJars = jars
-
 	system.outputDir, system.outputDeps = TransformJarsToSystemModules(ctx, jars)
+
+	android.SetProvider(ctx, SystemModulesProvider, &SystemModulesProviderInfo{
+		HeaderJars:    jars,
+		OutputDir:     system.outputDir,
+		OutputDirDeps: system.outputDeps,
+	})
 }
 
 // ComponentDepsMutator is called before prebuilt modules without a corresponding source module are
diff --git a/java/system_modules_test.go b/java/system_modules_test.go
index 336dd21..1a8d0b5 100644
--- a/java/system_modules_test.go
+++ b/java/system_modules_test.go
@@ -182,11 +182,7 @@
 	for _, tc := range testCases {
 		res := android.GroupFixturePreparers(
 			prepareForJavaTest,
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 		).RunTestWithBp(t, fmt.Sprintf(bp, tc.selectedDependencyName))
 
 		// check that rdep gets the correct variation of system_modules
diff --git a/sdk/bootclasspath_fragment_sdk_test.go b/sdk/bootclasspath_fragment_sdk_test.go
index 7048a15..7ee548f 100644
--- a/sdk/bootclasspath_fragment_sdk_test.go
+++ b/sdk/bootclasspath_fragment_sdk_test.go
@@ -276,11 +276,7 @@
 		// Add a platform_bootclasspath that depends on the fragment.
 		fixtureAddPlatformBootclasspathForBootclasspathFragment("myapex", "mybootclasspathfragment"),
 
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 		// Make sure that we have atleast one platform library so that we can check the monolithic hiddenapi
 		// file creation.
 		java.FixtureConfigureBootJars("platform:foo"),
@@ -799,11 +795,7 @@
 		// Add a platform_bootclasspath that depends on the fragment.
 		fixtureAddPlatformBootclasspathForBootclasspathFragment("myapex", "mybootclasspathfragment"),
 
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 
 		android.MockFS{
 			"my-blocked.txt":                   nil,
@@ -1053,11 +1045,7 @@
 			variables.Platform_version_active_codenames = []string{"VanillaIceCream"}
 		}),
 
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 
 		android.FixtureWithRootAndroidBp(`
 			sdk {
diff --git a/sdk/java_sdk_test.go b/sdk/java_sdk_test.go
index 0a5483b..0fb5c70 100644
--- a/sdk/java_sdk_test.go
+++ b/sdk/java_sdk_test.go
@@ -45,11 +45,7 @@
 	java.PrepareForTestWithJavaDefaultModules,
 	java.PrepareForTestWithJavaSdkLibraryFiles,
 	java.FixtureWithLastReleaseApis("myjavalib"),
-	android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-		variables.BuildFlags = map[string]string{
-			"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-		}
-	}),
+	android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 )
 
 // Contains tests for SDK members provided by the java package.
@@ -666,11 +662,7 @@
 			"1": {"myjavalib"},
 			"2": {"myjavalib"},
 		}),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		sdk {
 			name: "mysdk",
@@ -1313,11 +1305,7 @@
 func TestSnapshotWithJavaSdkLibrary_CompileDex(t *testing.T) {
 	result := android.GroupFixturePreparers(
 		prepareForSdkTestWithJavaSdkLibrary,
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		sdk {
 			name: "mysdk",
diff --git a/sdk/sdk_test.go b/sdk/sdk_test.go
index 4894210..057b370 100644
--- a/sdk/sdk_test.go
+++ b/sdk/sdk_test.go
@@ -457,11 +457,7 @@
 			android.FixtureMergeEnv(map[string]string{
 				"SOONG_SDK_SNAPSHOT_TARGET_BUILD_RELEASE": "S",
 			}),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 		).RunTest(t)
 
 		CheckSnapshot(t, result, "mysdk", "",
@@ -573,11 +569,9 @@
 				"SOONG_SDK_SNAPSHOT_TARGET_BUILD_RELEASE": "S",
 			}),
 			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-				}
 				variables.Platform_version_active_codenames = []string{"UpsideDownCake", "Tiramisu", "S-V2"}
 			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 		).RunTest(t)
 
 		CheckSnapshot(t, result, "mysdk", "",