--- /dev/null	2020-01-02 04:43:18.583999853 +0000
+++ new/test/lib/jdk/test/lib/ByteCodeLoader.java	2020-01-30 06:38:07.639722629 +0000
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2013, 2016, 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.test.lib;
+
+import java.security.SecureClassLoader;
+
+/**
+ * {@code ByteCodeLoader} can be used for easy loading of byte code already
+ * present in memory.
+ *
+ * {@code InMemoryCompiler} can be used for compiling source code in a string
+ * into byte code, which then can be loaded with {@code ByteCodeLoader}.
+ *
+ * @see InMemoryCompiler
+ */
+public class ByteCodeLoader extends SecureClassLoader {
+    private final String className;
+    private final byte[] byteCode;
+    private volatile Class<?> holder;
+
+    /**
+     * Creates a new {@code ByteCodeLoader} ready to load a class with the
+     * given name and the given byte code.
+     *
+     * @param className The name of the class
+     * @param byteCode The byte code of the class
+     */
+    public ByteCodeLoader(String className, byte[] byteCode) {
+        this.className = className;
+        this.byteCode = byteCode;
+    }
+
+    @Override
+    public Class<?> loadClass(String name) throws ClassNotFoundException {
+        if (!name.equals(className)) {
+            return super.loadClass(name);
+        }
+        if (holder == null) {
+            synchronized(this) {
+                if (holder == null) {
+                    holder = findClass(name);
+                }
+            }
+        }
+        return holder;
+    }
+
+    @Override
+    protected Class<?> findClass(String name) throws ClassNotFoundException {
+        if (!name.equals(className)) {
+            throw new ClassNotFoundException(name);
+        }
+
+        return defineClass(name, byteCode, 0, byteCode.length);
+    }
+
+    /**
+     * Utility method for creating a new {@code ByteCodeLoader} and then
+     * directly load the given byte code.
+     *
+     * @param className The name of the class
+     * @param byteCode The byte code for the class
+     * @throws ClassNotFoundException if the class can't be loaded
+     * @return A {@see Class} object representing the class
+     */
+    public static Class<?> load(String className, byte[] byteCode) throws ClassNotFoundException {
+        return new ByteCodeLoader(className, byteCode).loadClass(className);
+    }
+}