src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java

@@ -34,11 +34,10 @@
 import com.sun.tools.javac.tree.JCTree.*;
 import com.sun.tools.javac.tree.JCTree.JCMemberReference.ReferenceKind;
 import com.sun.tools.javac.tree.TreeMaker;
 import com.sun.tools.javac.tree.TreeTranslator;
 import com.sun.tools.javac.code.Attribute;
-import com.sun.tools.javac.code.Scope.WriteableScope;
 import com.sun.tools.javac.code.Symbol;
 import com.sun.tools.javac.code.Symbol.ClassSymbol;
 import com.sun.tools.javac.code.Symbol.DynamicMethodSymbol;
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
 import com.sun.tools.javac.code.Symbol.TypeSymbol;

@@ -125,10 +124,13 @@
     private final boolean verboseDeduplication;
 
     /** deduplicate lambda implementation methods */
     private final boolean deduplicateLambdas;
 
+    /** lambda proxy is a dynamic nestmate */
+    private final boolean nestmateLambdas;
+
     /** Flag for alternate metafactories indicating the lambda object is intended to be serializable */
     public static final int FLAG_SERIALIZABLE = 1 << 0;
 
     /** Flag for alternate metafactories indicating the lambda object has multiple targets */
     public static final int FLAG_MARKERS = 1 << 1;

@@ -166,10 +168,11 @@
         debugLinesOrVars = options.isSet(Option.G)
                 || options.isSet(Option.G_CUSTOM, "lines")
                 || options.isSet(Option.G_CUSTOM, "vars");
         verboseDeduplication = options.isSet("debug.dumpLambdaToMethodDeduplication");
         deduplicateLambdas = options.getBoolean("deduplicateLambdas", true);
+        nestmateLambdas = Target.instance(context).runtimeUseNestAccess();
     }
     // </editor-fold>
 
     class DedupedLambda {
         private final MethodSymbol symbol;

@@ -2251,10 +2254,24 @@
                 //when 292 issue is fixed we should remove this and change the backend
                 //code to always generate a method handle to an accessible method
                 return tree.ownerAccessible;
             }
 
+            /**
+             * This method should be called only when target release <= 14
+             * where LambdaMetaFactory does not spin nestmate classes.
+             *
+             * This method should be removed when --release 14 is not supported.
+             */
+            boolean isPrivateInOtherClass() {
+                assert !nestmateLambdas;
+                return  (tree.sym.flags() & PRIVATE) != 0 &&
+                        !types.isSameType(
+                              types.erasure(tree.sym.enclClass().asType()),
+                              types.erasure(owner.enclClass().asType()));
+            }
+
             boolean isProtectedInSuperClassOfEnclosingClassInOtherPackage() {
                 return ((tree.sym.flags() & PROTECTED) != 0 &&
                         tree.sym.packge() != owner.packge());
             }
 

@@ -2291,10 +2308,11 @@
             final boolean needsConversionToLambda() {
                 return interfaceParameterIsIntersectionOrUnionType() ||
                         isSuper ||
                         needsVarArgsConversion() ||
                         isArrayOp() ||
+                        (!nestmateLambdas && isPrivateInOtherClass()) ||
                         isProtectedInSuperClassOfEnclosingClassInOtherPackage() ||
                         !receiverAccessible() ||
                         (tree.getMode() == ReferenceMode.NEW &&
                           tree.kind != ReferenceKind.ARRAY_CTOR &&
                           (tree.sym.owner.isLocal() || tree.sym.owner.isInner()));