--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jvmci/jdk.internal.jvmci.runtime.test/src/jdk/internal/jvmci/runtime/test/RedefineClassTest.java	Wed Aug 12 12:11:33 2015 +0200
@@ -0,0 +1,168 @@
+/*
+ * Copyright (c) 2011, 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.
+ */
+package jdk.internal.jvmci.runtime.test;
+
+import static org.junit.Assume.*;
+
+import java.io.*;
+import java.lang.instrument.*;
+import java.lang.management.*;
+import java.lang.reflect.*;
+import java.nio.file.*;
+import java.security.*;
+import java.util.*;
+import java.util.jar.*;
+
+import javax.tools.*;
+
+import jdk.internal.jvmci.meta.*;
+
+import org.junit.*;
+
+/**
+ * Tests that {@link ResolvedJavaMethod}s are safe in the context of class redefinition being used
+ * to redefine the method to which they refer.
+ */
+public class RedefineClassTest extends TypeUniverse {
+
+    static class Foo {
+        public static Object getName() {
+            return "foo";
+        }
+    }
+
+    @Ignore("JVMCI is not yet class redefinition safe")
+    @Test
+    public void test() throws Throwable {
+
+        Method fooMethod = Foo.class.getDeclaredMethod("getName");
+
+        ResolvedJavaMethod foo1 = metaAccess.lookupJavaMethod(fooMethod);
+        ResolvedJavaMethod foo2 = metaAccess.lookupJavaMethod(fooMethod);
+
+        String foo1Code = Arrays.toString(foo1.getCode());
+        String foo2Code = Arrays.toString(foo2.getCode());
+
+        Assert.assertEquals("foo", Foo.getName());
+
+        redefineFoo();
+        System.gc();
+
+        // Make sure the transformation happened
+        Assert.assertEquals("bar", Foo.getName());
+
+        Assert.assertEquals(foo1Code, Arrays.toString(foo1.getCode()));
+        Assert.assertEquals(foo2Code, Arrays.toString(foo1.getCode()));
+    }
+
+    /**
+     * Adds the class file bytes for a given class to a JAR stream.
+     */
+    static void add(JarOutputStream jar, Class<?> c) throws IOException {
+        String name = c.getName();
+        String classAsPath = name.replace('.', '/') + ".class";
+        jar.putNextEntry(new JarEntry(classAsPath));
+
+        InputStream stream = c.getClassLoader().getResourceAsStream(classAsPath);
+
+        int nRead;
+        byte[] buf = new byte[1024];
+        while ((nRead = stream.read(buf, 0, buf.length)) != -1) {
+            jar.write(buf, 0, nRead);
+        }
+
+        jar.closeEntry();
+    }
+
+    protected void redefineFoo() throws Exception {
+        Manifest manifest = new Manifest();
+        manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
+        Attributes mainAttrs = manifest.getMainAttributes();
+        mainAttrs.putValue("Agent-Class", FooAgent.class.getName());
+        mainAttrs.putValue("Can-Redefine-Classes", "true");
+        mainAttrs.putValue("Can-Retransform-Classes", "true");
+
+        Path jar = Files.createTempFile("myagent", ".jar");
+        try {
+            JarOutputStream jarStream = new JarOutputStream(new FileOutputStream(jar.toFile()), manifest);
+            add(jarStream, FooAgent.class);
+            add(jarStream, FooTransformer.class);
+            jarStream.close();
+
+            loadAgent(jar);
+        } finally {
+            Files.deleteIfExists(jar);
+        }
+    }
+
+    public static void loadAgent(Path agent) throws Exception {
+        String vmName = ManagementFactory.getRuntimeMXBean().getName();
+        int p = vmName.indexOf('@');
+        assumeTrue("VM name not in <pid>@<host> format: " + vmName, p != -1);
+        String pid = vmName.substring(0, p);
+        ClassLoader cl = ToolProvider.getSystemToolClassLoader();
+        Class<?> c = Class.forName("com.sun.tools.attach.VirtualMachine", true, cl);
+        Method attach = c.getDeclaredMethod("attach", String.class);
+        Method loadAgent = c.getDeclaredMethod("loadAgent", String.class, String.class);
+        Method detach = c.getDeclaredMethod("detach");
+        Object vm = attach.invoke(null, pid);
+        loadAgent.invoke(vm, agent.toString(), "");
+        detach.invoke(vm);
+    }
+
+    public static class FooAgent {
+
+        public static void agentmain(@SuppressWarnings("unused") String args, Instrumentation inst) throws Exception {
+            if (inst.isRedefineClassesSupported() && inst.isRetransformClassesSupported()) {
+                inst.addTransformer(new FooTransformer(), true);
+                Class<?>[] allClasses = inst.getAllLoadedClasses();
+                for (int i = 0; i < allClasses.length; i++) {
+                    Class<?> c = allClasses[i];
+                    if (c == Foo.class) {
+                        inst.retransformClasses(new Class[]{c});
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * This transformer replaces the first instance of the constant "foo" in the class file for
+     * {@link Foo} with "bar".
+     */
+    static class FooTransformer implements ClassFileTransformer {
+
+        @Override
+        public byte[] transform(ClassLoader cl, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {
+            if (Foo.class.equals(classBeingRedefined)) {
+                String cf = new String(classfileBuffer);
+                int i = cf.indexOf("foo");
+                Assert.assertTrue("cannot find \"foo\" constant in " + Foo.class.getSimpleName() + "'s class file", i > 0);
+                classfileBuffer[i] = 'b';
+                classfileBuffer[i + 1] = 'a';
+                classfileBuffer[i + 2] = 'r';
+            }
+            return classfileBuffer;
+        }
+    }
+}