8067422: Lambda method names are unnecessarily unstable

Summary: Lambda method numbers are now assigned per class for non-serializable lambdas.
Reviewed-by: mcimadamore, rfield, vromero

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

@@ -1179,12 +1179,14 @@ public class LambdaToMethod extends TreeTranslator {
         @Override
         public void visitClassDef(JCClassDecl tree) {
             List<Frame> prevStack = frameStack;
+            int prevLambdaCount = lambdaCount;
             SyntheticMethodNameCounter prevSyntheticMethodNameCounts =
                     syntheticMethodNameCounts;
             Map<ClassSymbol, Symbol> prevClinits = clinits;
             DiagnosticSource prevSource = log.currentSource();
             try {
                 log.useSource(tree.sym.sourcefile);
+                lambdaCount = 0;
                 syntheticMethodNameCounts = new SyntheticMethodNameCounter();
                 prevClinits = new HashMap<ClassSymbol, Symbol>();
                 if (tree.sym.owner.kind == MTH) {
@@ -1211,6 +1213,7 @@ public class LambdaToMethod extends TreeTranslator {
             finally {
                 log.useSource(prevSource.getFile());
                 frameStack = prevStack;
+                lambdaCount = prevLambdaCount;
                 syntheticMethodNameCounts = prevSyntheticMethodNameCounts;
                 clinits = prevClinits;
             }

test/tools/javac/lambda/lambdaNaming/TestNonSerializableLambdaNameStability.java

+/*
+ * Copyright (c) 2014, 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.
+ */
+
+/*
+ * @test
+ * @bug 8067422
+ * @summary Check that the lambda names are not unnecessarily unstable
+ * @run main TestNonSerializableLambdaNameStability
+ */
+
+import com.sun.tools.classfile.ClassFile;
+import com.sun.tools.classfile.Method;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import javax.tools.FileObject;
+import javax.tools.ForwardingJavaFileManager;
+import javax.tools.JavaCompiler;
+import javax.tools.JavaFileManager;
+import javax.tools.JavaFileObject;
+import javax.tools.JavaFileObject.Kind;
+import javax.tools.SimpleJavaFileObject;
+import javax.tools.ToolProvider;
+
+public class TestNonSerializableLambdaNameStability {
+
+    public static void main(String... args) throws Exception {
+        new TestNonSerializableLambdaNameStability().run();
+    }
+
+    String lambdaSource = "public class L%d {\n" +
+                          "    public static class A {\n" +
+                          "        private Runnable r = () -> { };\n" +
+                          "    }\n" +
+                          "    public static class B {\n" +
+                          "        private Runnable r = () -> { };\n" +
+                          "    }\n" +
+                          "    private Runnable r = () -> { };\n" +
+                          "}\n";
+
+    String expectedLambdaMethodName = "lambda$new$0";
+
+    void run() throws Exception {
+        List<JavaFileObject> sources = new ArrayList<>();
+
+        for (int i = 0; i < 3; i++) {
+            sources.add(new SourceJavaFileObject("L" + i, String.format(lambdaSource, i)));
+        }
+
+        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
+
+        try (MemoryFileManager fm = new MemoryFileManager(compiler.getStandardFileManager(null, null, null))) {
+            if (!compiler.getTask(null, fm, null, null, null, sources).call()) {
+                throw new AssertionError("Compilation failed!");
+            }
+
+            for (String file : fm.name2Content.keySet()) {
+                byte[] fileBytes = fm.name2Content.get(file);
+                try (InputStream in = new ByteArrayInputStream(fileBytes)) {
+                    boolean foundLambdaMethod = false;
+                    ClassFile cf = ClassFile.read(in);
+                    StringBuilder seenMethods = new StringBuilder();
+                    String sep = "";
+                    for (Method m : cf.methods) {
+                        String methodName = m.getName(cf.constant_pool);
+                        if (expectedLambdaMethodName.equals(methodName)) {
+                            foundLambdaMethod = true;
+                            break;
+                        }
+                        seenMethods.append(sep);
+                        seenMethods.append(methodName);
+                        sep = ", ";
+                    }
+
+                    if (!foundLambdaMethod) {
+                        throw new AbstractMethodError("Did not find the lambda method, " +
+                                                      "found methods: " + seenMethods.toString());
+                    }
+                }
+            }
+        }
+    }
+
+    class MemoryFileManager extends ForwardingJavaFileManager<JavaFileManager> {
+
+        final Map<String, byte[]> name2Content = new HashMap<>();
+
+        public MemoryFileManager(JavaFileManager fileManager) {
+            super(fileManager);
+        }
+
+        @Override
+        public JavaFileObject getJavaFileForOutput(Location location, String className, Kind kind, FileObject sibling) throws IOException {
+            try {
+                return new SimpleJavaFileObject(new URI("mem://" + className.replace('.', '/') + kind.extension), kind) {
+                    @Override public OutputStream openOutputStream() throws IOException {
+                        return new ByteArrayOutputStream() {
+                            @Override public void close() throws IOException {
+                                super.close();
+                                name2Content.put(className, toByteArray());
+                            }
+                        };
+                    }
+                };
+            } catch (URISyntaxException ex) {
+                throw new AssertionError(ex);
+            }
+        }
+
+    }
+
+    class SourceJavaFileObject extends SimpleJavaFileObject {
+
+        private final String code;
+
+        public SourceJavaFileObject(String name, String code) throws URISyntaxException {
+            super(new URI("mem:///" + name + ".java"), Kind.SOURCE);
+            this.code = code;
+        }
+
+        @Override
+        public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {
+            return code;
+        }
+
+    }
+}