--- /dev/null	2016-10-25 08:46:44.038854975 +0200
+++ new/src/share/classes/sun/evtracing/processing/statistics/MonitorContender.java	2016-10-25 10:40:48.749803722 +0200
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2014, 2015, Dynatrace and/or its affiliates. All rights reserved.
+ * 
+ * This file is part of the Lock Contention Tracing Subsystem for the HotSpot
+ * Virtual Machine, which is developed at Christian Doppler Laboratory on
+ * Monitoring and Evolution of Very-Large-Scale Software Systems. Please
+ * contact us at <http://mevss.jku.at/> if you need additional information
+ * or have any questions.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ *
+ */ 
+package sun.evtracing.processing.statistics;
+
+import sun.evtracing.parser.MonitorContendedEnterEvent;
+import sun.evtracing.parser.MonitorContendedEnteredEvent;
+import sun.evtracing.parser.MonitorContendedExitedEvent;
+import sun.evtracing.parser.MonitorEnterWait;
+import sun.evtracing.parser.MonitorEnteredFlags;
+import sun.evtracing.parser.MonitorEvent;
+import sun.evtracing.parser.TraceEventType;
+import sun.evtracing.parser.metadata.JavaStack;
+import sun.evtracing.parser.metadata.JavaThread;
+import sun.evtracing.processing.Sanity;
+import sun.evtracing.processing.statistics.aggregator.ContentionProcessor;
+import sun.evtracing.processing.statistics.metadata.Contention;
+import sun.evtracing.processing.statistics.metadata.Group;
+import sun.evtracing.processing.statistics.metadata.JavaObjectStack;
+
+public class MonitorContender {
+
+	private final JavaObjectStack objectStack;
+	private final ContentionProcessor processor;
+	private final MonitorContendedEnterEvent enter;
+
+	private MonitorEvent lastEvent;
+
+	public static MonitorContender forEnter(JavaObjectStack objectStack, MonitorContendedEnterEvent event, ContentionProcessor processor) {
+		return new MonitorContender(objectStack, event, processor);
+	}
+
+	private MonitorContender(JavaObjectStack objectStack, MonitorContendedEnterEvent event, ContentionProcessor processor) {
+		this.objectStack = objectStack;
+		this.enter = event;
+		this.processor = processor;
+		this.lastEvent = event;
+	}
+
+	private Group group() {
+		if (enter.afterWait() != MonitorEnterWait.NoWait) {
+			return Group.MonitorWaitReentry;
+		}
+		return Group.Monitors;
+	}
+
+	private boolean wasEntered() {
+		return (lastEvent.type() == TraceEventType.MonitorContendedEntered);
+	}
+
+	void contenderExitedMonitor(MonitorContendedExitedEvent exit) {
+		assert !wasEntered();
+		long startTime = lastEvent.timestamp();
+		long duration = exit.timestamp() - startTime;
+		processor.submit(new Contention(group(), enter.thread().metadata(), exit.thread().metadata(), enter.stack().metadata(), exit.stack().metadata(), objectStack, startTime, duration));
+		lastEvent = exit;
+	}
+
+	void monitorContendedEntered(MonitorContendedEnteredEvent entered) {
+		assert !wasEntered();
+		if (entered.flags().contains(MonitorEnteredFlags.Queued)) {
+			if (entered.flags().contains(MonitorEnteredFlags.Parked)) {
+				Sanity.warnIf(lastEvent == enter, "entered monitor after parking without prior contender exit (rare race)");					
+			} else {
+				Sanity.warnIf(lastEvent == enter, "entered monitor after queueing without prior contender exit (race)");					
+			}
+		} else {
+			// the thread managed to obtain the lock only by spinning, not entering
+			// itself on any queue. therefore, the contender could not have noticed it
+			// and has not written an exit event unless another thread was waiting.
+		}
+		// attribute period between last exit and entered to unknown
+		long startTime = lastEvent.timestamp();
+		long duration = entered.timestamp() - startTime;
+		processor.submit(new Contention(group(), enter.thread().metadata(), JavaThread.UNKNOWN, enter.stack().metadata(), JavaStack.UNKNOWN, objectStack, startTime, duration));
+		lastEvent = entered;
+	}
+
+	void monitorContendedExited(long time) {
+		// nothing to do so far
+	}
+
+	@Override
+	public String toString() {
+		return enter.thread().metadata().toString() + " blocking on " + objectStack.toString();
+	}
+
+}