diff --git a/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java b/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
index 4c820ff..4336f61 100644
--- a/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
+++ b/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
@@ -236,7 +236,10 @@
       this.lambdaRewriter = new LambdaRewriter(appView);
       this.desugaredLibraryAPIConverter =
           new DesugaredLibraryAPIConverter(appView, Mode.GENERATE_CALLBACKS_AND_WRAPPERS);
-      this.backportedMethodRewriter = null;
+      this.backportedMethodRewriter =
+          options.testing.forceLibBackportsInL8CfToCf
+              ? new BackportedMethodRewriter(appView, this)
+              : null;
       this.twrCloseResourceRewriter = null;
       this.lambdaMerger = null;
       this.covariantReturnTypeAnnotationTransformer = null;
diff --git a/src/main/java/com/android/tools/r8/ir/desugar/BackportedMethodRewriter.java b/src/main/java/com/android/tools/r8/ir/desugar/BackportedMethodRewriter.java
index c56524e..e9a6faa 100644
--- a/src/main/java/com/android/tools/r8/ir/desugar/BackportedMethodRewriter.java
+++ b/src/main/java/com/android/tools/r8/ir/desugar/BackportedMethodRewriter.java
@@ -297,6 +297,14 @@
     private final Map<DexMethod, MethodProvider> rewritable = new IdentityHashMap<>();
 
     RewritableMethods(InternalOptions options, AppView<?> appView) {
+      if (options.testing.forceLibBackportsInL8CfToCf) {
+        DexItemFactory factory = options.itemFactory;
+        initializeJava9OptionalMethodProviders(factory);
+        initializeJava10OptionalMethodProviders(factory);
+        initializeJava11OptionalMethodProviders(factory);
+        initializeStreamMethodProviders(factory);
+        return;
+      }
       if (!options.shouldBackportMethods()) {
         return;
       }
diff --git a/src/main/java/com/android/tools/r8/utils/InternalOptions.java b/src/main/java/com/android/tools/r8/utils/InternalOptions.java
index ae119c2..c4481f5 100644
--- a/src/main/java/com/android/tools/r8/utils/InternalOptions.java
+++ b/src/main/java/com/android/tools/r8/utils/InternalOptions.java
@@ -1097,7 +1097,7 @@
     public PrintStream whyAreYouNotInliningConsumer = System.out;
     public boolean trackDesugaredAPIConversions =
         System.getProperty("com.android.tools.r8.trackDesugaredAPIConversions") != null;
-
+    public boolean forceLibBackportsInL8CfToCf = false;
     // TODO(b/144781417): This is disabled by default as some test apps appear to have such classes.
     public boolean allowNonAbstractClassesWithAbstractMethods = true;
 
diff --git a/src/test/java/com/android/tools/r8/desugar/desugaredlibrary/DesugaredLibraryTestBase.java b/src/test/java/com/android/tools/r8/desugar/desugaredlibrary/DesugaredLibraryTestBase.java
index 628fbfe..b68997a 100644
--- a/src/test/java/com/android/tools/r8/desugar/desugaredlibrary/DesugaredLibraryTestBase.java
+++ b/src/test/java/com/android/tools/r8/desugar/desugaredlibrary/DesugaredLibraryTestBase.java
@@ -82,7 +82,7 @@
       // If we compile extended library here, it means we use TestNG.
       // TestNG requires annotations, hence we disable AnnotationRemoval.
       // This implies that extra warning are generated if this is set.
-      boolean disableL8AnnotationRemovalForTesting = !additionalProgramFiles.isEmpty();
+      boolean extraFiles = !additionalProgramFiles.isEmpty();
       ArrayList<Path> extraPaths = new ArrayList<>(additionalProgramFiles);
       TestDiagnosticMessagesImpl diagnosticsHandler = new TestDiagnosticMessagesImpl();
       Path desugaredLib = temp.newFolder().toPath().resolve("desugar_jdk_libs_dex.zip");
@@ -104,11 +104,12 @@
       ToolHelper.runL8(
           l8Builder.build(),
           options -> {
-            if (disableL8AnnotationRemovalForTesting) {
+            if (extraFiles) {
               options.testing.disableL8AnnotationRemoval = true;
+              options.testing.forceLibBackportsInL8CfToCf = true;
             }
           });
-      if (!disableL8AnnotationRemovalForTesting) {
+      if (!extraFiles) {
         assertTrue(
             diagnosticsHandler.getInfos().stream()
                 .noneMatch(