diff --git a/java/dexpreopt_bootjars.go b/java/dexpreopt_bootjars.go
index 3addc1a..2a84f14 100644
--- a/java/dexpreopt_bootjars.go
+++ b/java/dexpreopt_bootjars.go
@@ -262,7 +262,7 @@
 	apex, isApexModule := module.(android.ApexModule)
 	fromUpdatableApex := isApexModule && apex.Updatable()
 	if image.name == artBootImageName {
-		if isApexModule && len(apex.InApexes()) > 0 && allHavePrefix(apex.InApexes(), "com.android.art.") {
+		if isApexModule && strings.HasPrefix(apex.ApexVariationName(), "com.android.art.") {
 			// ok: found the jar in the ART apex
 		} else if isApexModule && apex.IsForPlatform() && Bool(module.(*Library).deviceProperties.Hostdex) {
 			// exception (skip and continue): special "hostdex" platform variant
@@ -272,17 +272,17 @@
 			return -1, nil
 		} else if fromUpdatableApex {
 			// error: this jar is part of an updatable apex other than ART
-			ctx.Errorf("module %q from updatable apexes %q is not allowed in the ART boot image", name, apex.InApexes())
+			ctx.Errorf("module '%s' from updatable apex '%s' is not allowed in the ART boot image", name, apex.ApexVariationName())
 		} else {
 			// error: this jar is part of the platform or a non-updatable apex
-			ctx.Errorf("module %q is not allowed in the ART boot image", name)
+			ctx.Errorf("module '%s' is not allowed in the ART boot image", name)
 		}
 	} else if image.name == frameworkBootImageName {
 		if !fromUpdatableApex {
 			// ok: this jar is part of the platform or a non-updatable apex
 		} else {
 			// error: this jar is part of an updatable apex
-			ctx.Errorf("module %q from updatable apexes %q is not allowed in the framework boot image", name, apex.InApexes())
+			ctx.Errorf("module '%s' from updatable apex '%s' is not allowed in the framework boot image", name, apex.ApexVariationName())
 		}
 	} else {
 		panic("unknown boot image: " + image.name)
@@ -291,15 +291,6 @@
 	return index, jar.DexJarBuildPath()
 }
 
-func allHavePrefix(list []string, prefix string) bool {
-	for _, s := range list {
-		if !strings.HasPrefix(s, prefix) {
-			return false
-		}
-	}
-	return true
-}
-
 // buildBootImage takes a bootImageConfig, creates rules to build it, and returns the image.
 func buildBootImage(ctx android.SingletonContext, image *bootImageConfig) *bootImageConfig {
 	// Collect dex jar paths for the boot image modules.
diff --git a/java/sdk_library.go b/java/sdk_library.go
index de16173..2aae42f 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -1376,22 +1376,22 @@
 	return android.Paths{jarPath.Path()}
 }
 
-// Get the apex names for module, nil if it is for platform.
-func getApexNamesForModule(module android.Module) []string {
+// Get the apex name for module, "" if it is for platform.
+func getApexNameForModule(module android.Module) string {
 	if apex, ok := module.(android.ApexModule); ok {
-		return apex.InApexes()
+		return apex.ApexVariationName()
 	}
 
-	return nil
+	return ""
 }
 
-// Check to see if the other module is within the same set of named APEXes as this module.
+// Check to see if the other module is within the same named APEX as this module.
 //
 // If either this or the other module are on the platform then this will return
 // false.
-func withinSameApexesAs(module android.ApexModule, other android.Module) bool {
-	names := module.InApexes()
-	return len(names) > 0 && reflect.DeepEqual(names, getApexNamesForModule(other))
+func withinSameApexAs(module android.ApexModule, other android.Module) bool {
+	name := module.ApexVariationName()
+	return name != "" && getApexNameForModule(other) == name
 }
 
 func (module *SdkLibrary) sdkJars(ctx android.BaseModuleContext, sdkVersion sdkSpec, headerJars bool) android.Paths {
@@ -1410,7 +1410,7 @@
 		// Only allow access to the implementation library in the following condition:
 		// * No sdk_version specified on the referencing module.
 		// * The referencing module is in the same apex as this.
-		if sdkVersion.kind == sdkPrivate || withinSameApexesAs(module, ctx.Module()) {
+		if sdkVersion.kind == sdkPrivate || withinSameApexAs(module, ctx.Module()) {
 			if headerJars {
 				return module.HeaderJars()
 			} else {
@@ -1949,7 +1949,7 @@
 	// For consistency with SdkLibrary make the implementation jar available to libraries that
 	// are within the same APEX.
 	implLibraryModule := module.implLibraryModule
-	if implLibraryModule != nil && withinSameApexesAs(module, ctx.Module()) {
+	if implLibraryModule != nil && withinSameApexAs(module, ctx.Module()) {
 		if headerJars {
 			return implLibraryModule.HeaderJars()
 		} else {