diff -r 000000000000 -r f90c822e73f8 test/runtime/testlibrary/ClassUnloadCommon.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/runtime/testlibrary/ClassUnloadCommon.java	Wed Apr 27 01:25:04 2016 +0800
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2013, 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.io.File;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+
+public class ClassUnloadCommon {
+    public static class TestFailure extends RuntimeException {
+        TestFailure(String msg) {
+            super(msg);
+        }
+    }
+
+    public static void failIf(boolean value, String msg) {
+        if (value) throw new TestFailure("Test failed: " + msg);
+    }
+
+    private static volatile Object dummy = null;
+    private static void allocateMemory(int kilobytes) {
+        ArrayList<byte[]> l = new ArrayList<>();
+        dummy = l;
+        for (int i = kilobytes; i > 0; i -= 1) {
+            l.add(new byte[1024]);
+        }
+        l = null;
+        dummy = null;
+    }
+
+    public static void triggerUnloading() {
+        allocateMemory(16 * 1024); // yg size is 8m with cms, force young collection
+        System.gc();
+    }
+
+    public static ClassLoader newClassLoader() {
+        try {
+            return new URLClassLoader(new URL[] {
+                Paths.get(System.getProperty("test.classes",".") + File.separatorChar + "classes").toUri().toURL(),
+            }, null);
+        } catch (MalformedURLException e){
+            throw new RuntimeException("Unexpected URL conversion failure", e);
+        }
+    }
+
+}