diff --git a/java/bootclasspath_fragment.go b/java/bootclasspath_fragment.go
index bb542c4..7577316 100644
--- a/java/bootclasspath_fragment.go
+++ b/java/bootclasspath_fragment.go
@@ -538,7 +538,7 @@
 	global := dexpreopt.GetGlobalConfig(ctx)
 
 	possibleUpdatableModules := gatherPossibleApexModuleNamesAndStems(ctx, b.properties.Contents, bootclasspathFragmentContentDepTag)
-	jars := global.ApexBootJars.Filter(possibleUpdatableModules)
+	jars, unknown := global.ApexBootJars.Filter(possibleUpdatableModules)
 
 	// TODO(satayev): for apex_test we want to include all contents unconditionally to classpaths
 	// config. However, any test specific jars would not be present in ApexBootJars. Instead,
@@ -546,6 +546,12 @@
 	// This is an exception to support end-to-end test for SdkExtensions, until such support exists.
 	if android.InList("test_framework-sdkextensions", possibleUpdatableModules) {
 		jars = jars.Append("com.android.sdkext", "test_framework-sdkextensions")
+	} else if global.ApexBootJars.Len() != 0 && !android.IsModuleInVersionedSdk(ctx.Module()) {
+		unknown = android.RemoveListFromList(unknown, b.properties.Coverage.Contents)
+		_, unknown = android.RemoveFromList("core-icu4j", unknown)
+		if len(unknown) > 0 {
+			ctx.ModuleErrorf("%s in contents must also be declared in PRODUCT_APEX_BOOT_JARS", unknown)
+		}
 	}
 	return jars
 }