8164714: Constructor.newInstance creates instance of inner class with null outer class

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -105,6 +105,7 @@ public static Lower instance(Context context) {
     private final boolean disableProtectedAccessors; // experimental
     private final PkgInfo pkginfoOpt;
     private final boolean optimizeOuterThis;
+    private final boolean nullCheckOuterThis;
     private final boolean useMatchException;
     private final HashMap<TypePairs, String> typePairToName;
     private int variableIndex = 0;
@@ -134,6 +135,8 @@ protected Lower(Context context) {
         optimizeOuterThis =
             target.optimizeOuterThis() ||
             options.getBoolean("optimizeOuterThis", false);
+        nullCheckOuterThis = options.getBoolean("nullCheckOuterThis",
+            target.nullCheckOuterThisByDefault());
         disableProtectedAccessors = options.isSet("disableProtectedAccessors");
         Source source = Source.instance(context);
         Preview preview = Preview.instance(context);
@@ -1794,18 +1797,27 @@ JCStatement initField(int pos, Symbol rhs, Symbol lhs) {
                     make.Ident(rhs)).setType(lhs.erasure(types)));
     }
 
-    /** Return tree simulating the assignment {@code this.this$n = this$n}.
+    /**
+     * Return tree simulating null checking outer this and/or assigning. This is
+     * called when a null check is required (nullCheckOuterThis), or a synthetic
+     * field is generated (stores).
      */
-    JCStatement initOuterThis(int pos, VarSymbol rhs) {
+    JCStatement initOuterThis(int pos, VarSymbol rhs, boolean stores) {
         Assert.check(rhs.owner.kind == MTH);
-        VarSymbol lhs = outerThisStack.head;
-        Assert.check(rhs.owner.owner == lhs.owner);
+        Assert.check(nullCheckOuterThis || stores); // One of the flags must be true
         make.at(pos);
-        return
-            make.Exec(
-                make.Assign(
+        JCExpression expression = make.Ident(rhs);
+        if (nullCheckOuterThis) {
+            expression = attr.makeNullCheck(expression);
+        }
+        if (stores) {
+            VarSymbol lhs = outerThisStack.head;
+            Assert.check(rhs.owner.owner == lhs.owner);
+            expression = make.Assign(
                     make.Select(make.This(lhs.owner.erasure(types)), lhs),
-                    make.Ident(rhs)).setType(lhs.erasure(types)));
+                    expression).setType(lhs.erasure(types));
+        }
+        return make.Exec(expression);
     }
 
 /* ************************************************************************
@@ -2210,15 +2222,22 @@ public void visitClassDef(JCClassDecl tree) {
         }
         // If this$n was accessed, add the field definition and prepend
         // initializer code to any super() invocation to initialize it
-        if (currentClass.hasOuterInstance() && shouldEmitOuterThis(currentClass)) {
-            tree.defs = tree.defs.prepend(otdef);
-            enterSynthetic(tree.pos(), otdef.sym, currentClass.members());
+        // otherwise prepend enclosing instance null check code if required
+        emitOuter:
+        if (currentClass.hasOuterInstance()) {
+            boolean storesThis = shouldEmitOuterThis(currentClass);
+            if (storesThis) {
+                tree.defs = tree.defs.prepend(otdef);
+                enterSynthetic(tree.pos(), otdef.sym, currentClass.members());
+            } else if (!nullCheckOuterThis) {
+                break emitOuter;
+            }
 
             for (JCTree def : tree.defs) {
                 if (TreeInfo.isConstructor(def)) {
                     JCMethodDecl mdef = (JCMethodDecl)def;
                     if (TreeInfo.hasConstructorCall(mdef, names._super)) {
-                        List<JCStatement> initializer = List.of(initOuterThis(mdef.body.pos, mdef.params.head.sym));
+                        List<JCStatement> initializer = List.of(initOuterThis(mdef.body.pos, mdef.params.head.sym, storesThis)) ;
                         TreeInfo.mapSuperCalls(mdef.body, supercall -> make.Block(0, initializer.append(supercall)));
                     }
                 }

src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/Target.java

@@ -238,4 +238,11 @@ public boolean optimizeOuterThis() {
     public boolean usesReferenceOnlySelectorTypes() {
         return compareTo(Target.JDK1_23) < 0;
     }
+
+    /**
+     * Should we emit a null check against incoming outer this argument by default?
+     */
+    public boolean nullCheckOuterThisByDefault() {
+        return compareTo(JDK1_25) >= 0;
+    }
 }

test/langtools/tools/javac/annotations/typeAnnotations/classfile/AnnotatedExtendsTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -59,7 +59,7 @@ public static strictfp void main(String args[]) throws Exception {
                 .classes(classPath.toString())
                 .run()
                 .getOutput(Task.OutputKind.DIRECT);
-        if (!javapOut.contains("0: #21(): CLASS_EXTENDS, type_index=65535"))
+        if (!javapOut.contains("0: #27(): CLASS_EXTENDS, type_index=65535"))
             throw new AssertionError("Expected output missing: " + javapOut);
     }
 }

test/langtools/tools/javac/nestmates/CheckNestmateAttrs.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -89,9 +89,9 @@ void run() {
         runCheck(params, new String [] {
                         "NestHost: class CheckNestmateAttrs",
                         "0: aload_0",
-                        "1: getfield      #1                  // Field this$1:LCheckNestmateAttrs$Inner;",
-                        "4: getfield      #13                 // Field CheckNestmateAttrs$Inner.this$0:LCheckNestmateAttrs;",
-                        "7: invokevirtual #19                 // Method CheckNestmateAttrs.test:()V",
+                        "1: getfield      #7                  // Field this$1:LCheckNestmateAttrs$Inner;",
+                        "4: getfield      #19                 // Field CheckNestmateAttrs$Inner.this$0:LCheckNestmateAttrs;",
+                        "7: invokevirtual #25                 // Method CheckNestmateAttrs.test:()V",
                         "10: return"
         });
 

test/langtools/tools/javac/outerThisNull/NoOuterThisNullChecks.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.lang.reflect.InvocationTargetException;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/*
+ * @test
+ * @bug 8164714
+ * @summary No null check for immediate enclosing instance for VM/reflective
+ *          invocation of inner classes for older versions or on request
+ *
+ * @clean *
+ * @compile -XDnullCheckOuterThis=false NoOuterThisNullChecks.java
+ * @run junit NoOuterThisNullChecks
+ *
+ * @clean *
+ * @compile --release 17 NoOuterThisNullChecks.java
+ * @run junit NoOuterThisNullChecks
+ */
+class NoOuterThisNullChecks {
+    static Stream<Class<?>> testClasses() {
+        return Stream.of(NoOuterThis.class, OuterThisField.class);
+    }
+
+    @MethodSource("testClasses")
+    @ParameterizedTest
+    void testNoOuter(Class<?> clz) {
+        assertDoesNotThrow(() -> clz.getDeclaredConstructor(NoOuterThisNullChecks.class).newInstance((Object) null));
+
+        MethodHandle mh = assertDoesNotThrow(() -> MethodHandles.lookup().findConstructor(clz, MethodType.methodType(void.class, NoOuterThisNullChecks.class)))
+                .asType(MethodType.methodType(Object.class, Object.class));
+        assertDoesNotThrow(() -> {
+            Object stub = mh.invokeExact((Object) null);
+        });
+    }
+
+    class NoOuterThis {}
+    class OuterThisField {
+        @Override
+        public String toString() {
+            return "outer this = " + NoOuterThisNullChecks.this;
+        }
+    }
+}

test/langtools/tools/javac/outerThisNull/OuterThisNullChecks.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.lang.reflect.InvocationTargetException;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/*
+ * @test
+ * @bug 8164714
+ * @summary Null check for immediate enclosing instance for VM/reflective
+ *          invocation of inner classes
+ *
+ * @clean *
+ * @compile OuterThisNullChecks.java
+ * @run junit OuterThisNullChecks
+ *
+ * @clean *
+ * @compile --release 17 -XDnullCheckOuterThis=true OuterThisNullChecks.java
+ * @run junit OuterThisNullChecks
+ */
+class OuterThisNullChecks {
+    static Stream<Class<?>> testClasses() {
+        return Stream.of(NoOuterThis.class, OuterThisField.class);
+    }
+
+    @MethodSource("testClasses")
+    @ParameterizedTest
+    void testNoOuter(Class<?> clz) {
+        var ite = assertThrows(InvocationTargetException.class, () -> clz.getDeclaredConstructor(OuterThisNullChecks.class).newInstance((Object) null));
+        assertInstanceOf(NullPointerException.class, ite.getCause());
+
+        MethodHandle mh = assertDoesNotThrow(() -> MethodHandles.lookup().findConstructor(clz, MethodType.methodType(void.class, OuterThisNullChecks.class)))
+                .asType(MethodType.methodType(Object.class, Object.class));
+        assertThrows(NullPointerException.class, () -> {
+            Object stub = mh.invokeExact((Object) null);
+        });
+    }
+
+    class NoOuterThis {}
+    class OuterThisField {
+        @Override
+        public String toString() {
+            return "outer this = " + OuterThisNullChecks.this;
+        }
+    }
+}

test/langtools/tools/javap/AnnoTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,58 +49,58 @@ void run() throws Exception {
 
         expect(out,
                 "RuntimeVisibleAnnotations:\n" +
-                "  0: #18(#19=B#20)\n" +
+                "  0: #24(#25=B#26)\n" +
                 "    AnnoTest$ByteAnno(\n" +
                 "      value=(byte) 42\n" +
                 "    )\n" +
-                "  1: #21(#19=S#22)\n" +
+                "  1: #27(#25=S#28)\n" +
                 "    AnnoTest$ShortAnno(\n" +
                 "      value=(short) 3\n" +
                 "    )");
         expect(out,
                 "RuntimeInvisibleAnnotations:\n" +
-                "  0: #24(#19=[J#25,J#27,J#29,J#31,J#33])\n" +
+                "  0: #30(#25=[J#31,J#33,J#35,J#37,J#39])\n" +
                 "    AnnoTest$ArrayAnno(\n" +
                 "      value=[1l,2l,3l,4l,5l]\n" +
                 "    )\n" +
-                "  1: #35(#19=Z#36)\n" +
+                "  1: #41(#25=Z#42)\n" +
                 "    AnnoTest$BooleanAnno(\n" +
                 "      value=false\n" +
                 "    )\n" +
-                "  2: #37(#38=c#39)\n" +
+                "  2: #43(#44=c#45)\n" +
                 "    AnnoTest$ClassAnno(\n" +
                 "      type=class Ljava/lang/Object;\n" +
                 "    )\n" +
-                "  3: #40(#41=e#42.#43)\n" +
+                "  3: #46(#47=e#48.#49)\n" +
                 "    AnnoTest$EnumAnno(\n" +
                 "      kind=Ljavax/lang/model/element/ElementKind;.PACKAGE\n" +
                 "    )\n" +
-                "  4: #44(#19=I#45)\n" +
+                "  4: #50(#25=I#51)\n" +
                 "    AnnoTest$IntAnno(\n" +
                 "      value=2\n" +
                 "    )\n" +
-                "  5: #46()\n" +
+                "  5: #52()\n" +
                 "    AnnoTest$IntDefaultAnno\n" +
-                "  6: #47(#48=s#49)\n" +
+                "  6: #53(#54=s#55)\n" +
                 "    AnnoTest$NameAnno(\n" +
                 "      name=\"NAME\"\n" +
                 "    )\n" +
-                "  7: #50(#51=D#52,#54=F#55)\n" +
+                "  7: #56(#57=D#58,#60=F#61)\n" +
                 "    AnnoTest$MultiAnno(\n" +
                 "      d=3.14159d\n" +
                 "      f=2.71828f\n" +
                 "    )\n" +
-                "  8: #56()\n" +
+                "  8: #62()\n" +
                 "    AnnoTest$SimpleAnno\n" +
-                "  9: #57(#19=@#44(#19=I#58))\n" +
+                "  9: #63(#25=@#50(#25=I#64))\n" +
                 "    AnnoTest$AnnoAnno(\n" +
                 "      value=@AnnoTest$IntAnno(\n" +
                 "        value=5\n" +
                 "      )\n" +
                 "    )");
         expect(out,
                 "RuntimeInvisibleTypeAnnotations:\n" +
-                "  0: #60(): CLASS_EXTENDS, type_index=0\n" +
+                "  0: #66(): CLASS_EXTENDS, type_index=0\n" +
                 "    AnnoTest$TypeAnno");
 
         if (errors > 0)

test/langtools/tools/javap/classfile/T6887895.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -57,7 +57,8 @@ void run() throws Exception {
                 "java/lang/Object",
                 "java/lang/String",
                 "T6887895",
-                "T6887895$Test"
+                "T6887895$Test",
+                "java/util/Objects",
         };
 
         Set<String> expect = new TreeSet<String>(Arrays.asList(expectNames));