--- /dev/null	2020-03-26 16:02:40.000000000 -0700
+++ new/test/hotspot/jtreg/runtime/HiddenClasses/StressHiddenClasses.java	2020-03-26 16:02:39.000000000 -0700
@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2020, 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
+ * @summary Stress defining hidden classes.
+ * @requires !vm.graal.enabled
+ * @library /test/lib
+ * @modules java.compiler
+ *          java.management
+ * @run main/othervm StressHiddenClasses
+ */
+
+import java.lang.invoke.MethodType;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodHandles.Lookup;
+import static java.lang.invoke.MethodHandles.Lookup.ClassOption.*;
+import jdk.test.lib.compiler.InMemoryJavaCompiler;
+
+// This test is based on vmTestbase/vm/mlvm/anonloader/share/StressClassLoadingTest.java
+public class StressHiddenClasses {
+
+    private static final int PARSE_TIMEOUT = 0;
+    private static final int ITERATIONS = 40000;
+
+    static byte klassbuf[] = InMemoryJavaCompiler.compile("TestClass",
+        "public class TestClass { " +
+        "    public static void concat(String one, String two) throws Throwable { " +
+        "        System.out.println(one + two);" +
+        " } } ");
+
+
+    public void run() throws Exception {
+        for (int x = 0; x < ITERATIONS; x++) {
+            Thread parserThread  = new Thread() {
+                public void run() {
+                    try {
+                        Lookup lookup = MethodHandles.lookup();
+                        Class<?> c = lookup.defineHiddenClass(klassbuf, true, NESTMATE).lookupClass();
+                    } catch (Throwable e) {
+                        throw new RuntimeException("Unexpected exception: " + e.toString());
+                    }
+                }
+            };
+
+            parserThread.start();
+            parserThread.join(PARSE_TIMEOUT);
+
+            if (parserThread.isAlive()) {
+                System.out.println("parser thread may be hung!");
+                StackTraceElement[] stack = parserThread.getStackTrace();
+                System.out.println("parser thread stack len: " + stack.length);
+                System.out.println(parserThread + " stack trace:");
+                for (int i = 0; i < stack.length; ++i) {
+                    System.out.println(parserThread + "\tat " + stack[i]);
+                }
+
+                parserThread.join(); // Wait until either thread finishes or test times out.
+            }
+        }
+    }
+
+
+    public static void main(String[] args) throws Throwable {
+        StressHiddenClasses shc = new StressHiddenClasses();
+        shc.run();
+    }
+}