--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/locks/DeadlockMaker.java	Mon Apr 30 18:10:24 2018 -0700
@@ -0,0 +1,161 @@
+/*
+ * Copyright (c) 2007, 2018, 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 nsk.share.locks;
+
+import java.util.*;
+import nsk.share.TestBug;
+import nsk.share.Wicket;
+
+/*
+ * Class used to create deadlocked threads. It is possible create 2 or more deadlocked thread, also
+ * is is possible to specify resource of which type should lock each deadlocked thread
+ */
+public class DeadlockMaker {
+    // create deadlock with 2 threads
+    // lockType1 and lockType2 - type of locking resources used for deadlock creation
+    public static DeadlockedThread[] createDeadlockedThreads(LockType lockType1, LockType lockType2) {
+        DeadlockedThread[] resultThreads = new DeadlockedThread[2];
+
+        Wicket step1 = new Wicket();
+        Wicket step2 = new Wicket();
+
+        Wicket readyWicket = new Wicket(2);
+
+        DeadlockLocker locker1 = createLocker(lockType1, step1, step2, readyWicket);
+        DeadlockLocker locker2 = createLocker(lockType2, step2, step1, readyWicket);
+        locker1.setInner(locker2);
+        locker2.setInner(locker1);
+
+        resultThreads[0] = new DeadlockedThread(locker1);
+        resultThreads[1] = new DeadlockedThread(locker2);
+
+        resultThreads[0].start();
+        resultThreads[1].start();
+
+        readyWicket.waitFor();
+
+        // additional check to be sure that all threads really blocked
+        waitForDeadlock(resultThreads);
+
+        return resultThreads;
+    }
+
+    // create deadlock with several threads
+    // locksTypes - type of locking resources used for deadlock creation
+    public static DeadlockedThread[] createDeadlockedThreads(List<LockType> locksTypes) {
+        if (locksTypes.size() < 2) {
+            throw new IllegalArgumentException("Need at least 2 threads for deadlock");
+        }
+
+        int threadsNumber = locksTypes.size();
+
+        DeadlockedThread[] resultThreads = new DeadlockedThread[threadsNumber];
+
+        Wicket readyWicket = new Wicket(threadsNumber);
+
+        DeadlockLocker deadlockLockers[] = new DeadlockLocker[threadsNumber];
+        Wicket stepWickets[] = new Wicket[threadsNumber];
+
+        for (int i = 0; i < threadsNumber; i++)
+            stepWickets[i] = new Wicket();
+
+        int index1 = 0;
+        int index2 = 1;
+        for (int i = 0; i < threadsNumber; i++) {
+            Wicket step1 = stepWickets[index1];
+            Wicket step2 = stepWickets[index2];
+
+            deadlockLockers[i] = createLocker(locksTypes.get(i), step1, step2, readyWicket);
+
+            if (i > 0)
+                deadlockLockers[i - 1].setInner(deadlockLockers[i]);
+
+            index1 = (index1 + 1) % threadsNumber;
+            index2 = (index2 + 1) % threadsNumber;
+        }
+        deadlockLockers[threadsNumber - 1].setInner(deadlockLockers[0]);
+
+        for (int i = 0; i < threadsNumber; i++) {
+            resultThreads[i] = new DeadlockedThread(deadlockLockers[i]);
+            resultThreads[i].start();
+        }
+
+        readyWicket.waitFor();
+
+        // additional check to be sure that all threads really blocked
+        waitForDeadlock(resultThreads);
+
+        return resultThreads;
+    }
+
+    /*
+     * Wait when thread state will change to be sure that deadlock is really created
+     */
+    static private void waitForDeadlock(DeadlockedThread[] threads) {
+        Set<Thread.State> targetStates = new HashSet<Thread.State>();
+
+        // thread is waiting for a monitor lock to enter a synchronized block/method
+        targetStates.add(Thread.State.BLOCKED);
+
+        // thread calls LockSupport.park
+        targetStates.add(Thread.State.WAITING);
+
+        // thread calls LockSupport.parkNanos or LockSupport.parkUntil
+        targetStates.add(Thread.State.TIMED_WAITING);
+
+        for (Thread thread : threads) {
+            while (!targetStates.contains(thread.getState())) {
+                sleep(100);
+            }
+        }
+    }
+
+    static private void sleep(long millis) {
+        try {
+            Thread.sleep(millis);
+        } catch (InterruptedException e) {
+            System.out.println("Unexpected exception: " + e);
+            e.printStackTrace(System.out);
+
+            TestBug testBugException = new TestBug("Unexpected exception was throw: " + e);
+            testBugException.initCause(e);
+            throw testBugException;
+        }
+    }
+
+    // create locker with given type
+    public static DeadlockLocker createLocker(LockType type, Wicket step1, Wicket step2, Wicket readyWicket) {
+        switch (type) {
+        case SYNCHRONIZED_METHOD:
+            return new SynchronizedMethodLocker(step1, step2, readyWicket);
+        case SYNCHRONIZED_BLOCK:
+            return new SynchronizedBlockLocker(step1, step2, readyWicket);
+        case REENTRANT_LOCK:
+            return new ReentrantLockLocker(step1, step2, readyWicket);
+        case JNI_LOCK:
+            return new JNIMonitorLocker(step1, step2, readyWicket);
+        }
+
+        throw new IllegalArgumentException("Unsupported lock type: " + type);
+    }
+}