eclipse_newsletter/2014/january/content/en_article2.php - gerrit/www.eclipse.org/community - Git at Google

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 /*******************************************************************************
  * Copyright (c) 2015 Eclipse Foundation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *    Eric Poirier (Eclipse Foundation) - Initial implementation
  *******************************************************************************/
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 <h1 class="article-title"><?php echo $pageTitle; ?></h1>
   <h2>JVM Convergence</h2>

   <p>
     As Henrik St&aring;hl, VP of Product Management in the Java Platform
     Group at Oracle outlined Oracle’s JVM strategy at the JavaOne
     conference back in 2010, the high level plan presented to the
     JavaOne audience and on Henrik’s blog foresaw that the best features
     from HotSpot and JRockit would be merged into a single VM. Dubbed <i>JVM
       convergence</i>, this process was expected to take multiple years.
   </p>
   <p>While the first fruits of this labor showed up in JDK 7, the bulk
     of JVM convergence effort has been planned for JDK 8. A quick glance
     at the planned JDK 8 feature list, which is available on the
     corresponding OpenJDK Project’s web site, shows a number of
     improvements in the JVM area, like the removal of the permanent
     generation, that have been implemented for JDK 8 as part of the JVM
     convergence effort.</p>
   <p>Fortunately, you don’t have to wait until JDK 8 is released to
     benefit from a small selection of the new JVM features, as a few of
     them have, after careful backporting and testing, made their way
     into JDK 7 Update releases. One of the most notable of them is Java
     Mission Control, which is bundled with the HotSpot JVM starting with
     the release of Oracle JDK 7 Update 40 (7u40).</p>

   <h2>History</h2>

   <p>Java Mission Control’s ancestor is JRockit Mission Control, the
     production time profiling and diagnostics tools suite for the
     JRockit JVM. For in-depth background and information on the JRockit
     JVM and JRockit Mission Control, I’d recommend the book “Oracle
     JRockit: The Definitive Guide” by Marcus Hirt and Marcus Lagergren.</p>
   <p>What began as an effort to create tooling to analyze how real
     production systems were using the JRockit JVM, evolved into an
     efficient, low overhead way to gather and analyze telemetry data of
     applications running on the JRockit JVM, allowing the development
     team to reproduce and address customer issues without requiring
     access to their source code, or their production environment.</p>
   <p>
     Instead of using more traditional and invasive techniques like
     bytecode instrumentation (which has the obvious drawback that the so
     instrumented application being analyzed is no longer made up of the
     same bytecode that was running in production and exhibited some
     interesting behavior) or JVMTI, Java Mission Control relies on a
     ‘flight recorder’ feature in the HotSpot JVM - which is accordingly
     called <i>Java Flight Recorder</i>.
   </p>
   <p>Recordings of JVM telemetry data can be produced by the Java Flight
     Recorder on demand, analyzed directly or stored for later analysis
     inside Java Mission Control using the Flight Recorder tool. The data
     includes an execution profile, memory allocation and garbage
     collection statistics, optimization decisions, as well as
     information on I/O and locking events. Given that its focus is on
     gathering data with the lowest possible impact on the running
     application, Java Mission Control is suitable for use in both
     development and production environments.</p>

   <h2>Availability</h2>

   <p>Oracle Java Mission Control and Oracle Java Flight Recorder are
     commercial features, which are available as part of the Oracle Java
     SE Advanced product. They are freely available for download for
     development and evaluation purposes as part of Oracle JDK 7 Update
     40, as per the terms in the Oracle Binary Code License Agreement,
     but require an Oracle Java SE Advanced license for production use.</p>

   <h2>Getting Started</h2>

   <p>
     If you have downloaded and installed Oracle JDK 7 Update 40, or a
     later release, you can start Java Mission Control by running the jmc
     application in the <i>bin</i> directory of an Oracle JDK 7 Update 40
     installation. If you are an Eclipse user, you’ll be greeted by a
     familiar looking user interface - which may come as a surprise.
   </p>
   <p>Java Mission Control is built upon the Eclipse RCP technology. If
     you are interested in the background and details behind getting an
     Eclipse RCP based application into the JDK, I’d recommend the
     upcoming “Experiences from building one of the world's most
     distributed RCP apps” presentation at EclipseCon 2014 by Klara Ward
     and Marcus Hirt from Oracle. And of course, if you’d like to see
     Oracle Java Mission Control in action at EclipseCon, Marcus Hirt and
     David Lindholm have a session titled “The new profiling tools in the
     Oracle JDK!” that goes into the details.</p>
   <p>
     Besides the standalone Java Mission Control tool, if you instead
     prefer to run your development tools inside the Eclipse IDE, the
     Oracle Java Mission Control home page at <a target="_blank"
       href="http://download.oracle.com/technology/products/missioncontrol/updatesites/base/5.5.0/eclipse/">http://oracle.com/missioncontrol</a>
     provides a pointer to the Eclipse Update site for the respective set
     of plugins. For the best user experience, it is recommended to use
     Eclipse IDE 3.8.2. Please note that in that case you’ll need to run
     your Eclipse IDE on the JDK in order for all the feature of Java
     Mission Control to work as expected. Detailed installation
     instructions are linked off the Oracle Java Mission Control home
     page.
   </p>

   <h2>Using the JMX Console</h2>

   <p>If you are familiar with the JConsole utility in the JDK, you’ll
     find the Java Mission Control JXM Console easily accessible,
     providing you with a superset of the functionality. For a start, it
     lets you detect and connect to Java processes running either locally
     on your machine, or remotely, through the Java Discovery Protocol
     (JDP) or given a JMX agent URL.</p>
   <p>Once connected, the JMX console allows you to monitor and visualize
     the JMX data of the Java process, to take actions depending on the
     observed values triggering conditions, to store recorded data for
     later analysis, and, of course, to load it back into Java Mission
     Control to take a deeper look into the observed behavior.</p>
   <p>Typically, the JMX Console would be used to continuously monitor a
     running process, by observing a small set of data of interest like
     the CPU load or heap usage. Once a certain condition is met, the
     console could be configured to dump the Flight Recorder data, for
     example, for later evaluation.</p>

   <h2>The Java Flight Recorder</h2>

   <p>When something goes wrong unexpectedly, it’s very important to be
     able to find out the exact circumstances in order to track down the
     root cause of failure. The Java Flight Recorder can be thought of as
     such a tool for the HotSpot JVM - it efficiently records information
     about the JVM and its environment, for as long as it’s running. When
     something interesting happens, the recorded data can be dumped and
     stored for later, off-line analysis, or it can be simply stored on
     an ongoing basis. It has a low performance impact, less then 2% for
     typical Java applications, when collecting data and events.</p>

   <h2>Creating Flight Recordings</h2>

   <p>
     In order to create flight recordings, you have to explicitly enable
     the Java Flight Recorder in the HotSpot JVM you’d like to monitor by
     passing a few additional flags to it upon startup. For details,
     please consult the extensive Java Flight Recorder Runtime Guide
     available at <a target="_blank"
       href="http://docs.oracle.com/javase/7/docs/technotes/guides/jfr">http://docs.oracle.com/javase/7/docs/technotes/guides/jfr</a>.
   </p>
   <p>Recordings can be timed or continuous. Timed recordings run for a
     given amount of time, and stop automatically once the time is up.
     When you create a timed recording in Java Mission Control, it will
     be automatically stored, downloaded and loaded into the tool for
     analysis once the recording completes. Continuous recordings, on the
     other hand, run until they are stopped by the end user.</p>
   <p>While creating recordings directly from Java Mission Control is the
     easiest choice for developers, users who need more flexibility can
     use the jcmd command line tool, or pass command line flags to the
     HotSpot JVM to get the desired behavior.</p>

   <h2>Analyzing Flight Recordings</h2>

   <p>Once you load up a flight recording in Java Mission Control, you
     can look at a number of different areas like code, memory, threads,
     locks and I/O and analyze various aspects of runtime behavior of
     your application.</p>
   <p>For example, for CPU-bound applications, the code view in the user
     interface will let you drill down into hotspots of your application,
     and discover optimization opportunities. If you’re tuning the GC, or
     tracking down memory allocation issues, then you can use the memory
     view to get a detailed view on individual GC events, allocation
     sites, GC pauses, etc. You can visualize the latency profile of your
     application by looking at I/O and Threads views, and even drill down
     into a view representing individual events in the recording.</p>

   <h2>Summary</h2>

   <p>Fortunately, you don’t have to wait for Java 8 to try out Java
     Mission Control and Java Flight Recorder. If you’re curious about
     the Eclipse RCP based application in the Oracle JDK, as I hope you’d
     be, check out the jmc application in the bin directory, and give it
     a spin.</p>

   <h2>Resources</h2>
   <ul>
     <li><a target="_blank" href="http://download.oracle.com/technology/products/missioncontrol/updatesites/base/5.5.0/eclipse/">Oracle
         Java Mission Control home page</a></li>
     <li><a target="_blank"
       href="http://www.youtube.com/watch?v=WMEpRUgp9Y4">Demo video</a></li>
     <li><a target="_blank"
       href="https://forums.oracle.com/thread/2579717">FAQ</a></li>
     <li><a target="_blank" href="http://hirt.se/blog/?cat=3">Marcus
         Hirt’s blog</a></li>
     <li><a target="_blank"
       href="https://blogs.oracle.com/henrik/entry/oracles_jvm_strategy">Oracle’s
         JVM Strategy</a></li>
     <li><a target="_blank"
       href="http://openjdk.java.net/projects/jdk8/features">Planned JDK
         8 Features</a></li>
   </ul>

 <div class="bottomitem">
   <h3>About the Authors</h3>

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     <div class="col-sm-12">
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         <div class="col-sm-8">
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         src="/community/eclipse_newsletter/2014/january/images/DaliborTopic75.jpg"
         alt="dalibor topic" />
         </div>
         <div class="col-sm-16">
           <p class="author-name">
         Dalibor Topic<br />
         <a target="_blank" href="http://www.oracle.com/index.html">Oracle</a>
       </p>
       <ul class="author-link">
         <li><a target="_blank" href="http://robilad.livejournal.com/">Blog</a></li>
         <li><a target="_blank" href="https://twitter.com/robilad">Twitter</a></li>
         <!--<li><a target="_blank" href="https://plus.google.com/+IanSkerrett">Google +</a></li>
           $og-->
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	<?php
	/*******************************************************************************
	* Copyright (c) 2015 Eclipse Foundation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* Eric Poirier (Eclipse Foundation) - Initial implementation
	*******************************************************************************/
	?>

	<h1 class="article-title"><?php echo $pageTitle; ?></h1>
	<h2>JVM Convergence</h2>

	<p>
	As Henrik Ståhl, VP of Product Management in the Java Platform
	Group at Oracle outlined Oracle’s JVM strategy at the JavaOne
	conference back in 2010, the high level plan presented to the
	JavaOne audience and on Henrik’s blog foresaw that the best features
	from HotSpot and JRockit would be merged into a single VM. Dubbed <i>JVM
	convergence</i>, this process was expected to take multiple years.
	</p>
	<p>While the first fruits of this labor showed up in JDK 7, the bulk
	of JVM convergence effort has been planned for JDK 8. A quick glance
	at the planned JDK 8 feature list, which is available on the
	corresponding OpenJDK Project’s web site, shows a number of
	improvements in the JVM area, like the removal of the permanent
	generation, that have been implemented for JDK 8 as part of the JVM
	convergence effort.</p>
	<p>Fortunately, you don’t have to wait until JDK 8 is released to
	benefit from a small selection of the new JVM features, as a few of
	them have, after careful backporting and testing, made their way
	into JDK 7 Update releases. One of the most notable of them is Java
	Mission Control, which is bundled with the HotSpot JVM starting with
	the release of Oracle JDK 7 Update 40 (7u40).</p>

	<h2>History</h2>

	<p>Java Mission Control’s ancestor is JRockit Mission Control, the
	production time profiling and diagnostics tools suite for the
	JRockit JVM. For in-depth background and information on the JRockit
	JVM and JRockit Mission Control, I’d recommend the book “Oracle
	JRockit: The Definitive Guide” by Marcus Hirt and Marcus Lagergren.</p>
	<p>What began as an effort to create tooling to analyze how real
	production systems were using the JRockit JVM, evolved into an
	efficient, low overhead way to gather and analyze telemetry data of
	applications running on the JRockit JVM, allowing the development
	team to reproduce and address customer issues without requiring
	access to their source code, or their production environment.</p>
	<p>
	Instead of using more traditional and invasive techniques like
	bytecode instrumentation (which has the obvious drawback that the so
	instrumented application being analyzed is no longer made up of the
	same bytecode that was running in production and exhibited some
	interesting behavior) or JVMTI, Java Mission Control relies on a
	‘flight recorder’ feature in the HotSpot JVM - which is accordingly
	called <i>Java Flight Recorder</i>.
	</p>
	<p>Recordings of JVM telemetry data can be produced by the Java Flight
	Recorder on demand, analyzed directly or stored for later analysis
	inside Java Mission Control using the Flight Recorder tool. The data
	includes an execution profile, memory allocation and garbage
	collection statistics, optimization decisions, as well as
	information on I/O and locking events. Given that its focus is on
	gathering data with the lowest possible impact on the running
	application, Java Mission Control is suitable for use in both
	development and production environments.</p>

	<h2>Availability</h2>

	<p>Oracle Java Mission Control and Oracle Java Flight Recorder are
	commercial features, which are available as part of the Oracle Java
	SE Advanced product. They are freely available for download for
	development and evaluation purposes as part of Oracle JDK 7 Update
	40, as per the terms in the Oracle Binary Code License Agreement,
	but require an Oracle Java SE Advanced license for production use.</p>

	<h2>Getting Started</h2>

	<p>
	If you have downloaded and installed Oracle JDK 7 Update 40, or a
	later release, you can start Java Mission Control by running the jmc
	application in the <i>bin</i> directory of an Oracle JDK 7 Update 40
	installation. If you are an Eclipse user, you’ll be greeted by a
	familiar looking user interface - which may come as a surprise.
	</p>
	<p>Java Mission Control is built upon the Eclipse RCP technology. If
	you are interested in the background and details behind getting an
	Eclipse RCP based application into the JDK, I’d recommend the
	upcoming “Experiences from building one of the world's most
	distributed RCP apps” presentation at EclipseCon 2014 by Klara Ward
	and Marcus Hirt from Oracle. And of course, if you’d like to see
	Oracle Java Mission Control in action at EclipseCon, Marcus Hirt and
	David Lindholm have a session titled “The new profiling tools in the
	Oracle JDK!” that goes into the details.</p>
	<p>
	Besides the standalone Java Mission Control tool, if you instead
	prefer to run your development tools inside the Eclipse IDE, the
	Oracle Java Mission Control home page at <a target="_blank"
	href="http://download.oracle.com/technology/products/missioncontrol/updatesites/base/5.5.0/eclipse/">http://oracle.com/missioncontrol</a>
	provides a pointer to the Eclipse Update site for the respective set
	of plugins. For the best user experience, it is recommended to use
	Eclipse IDE 3.8.2. Please note that in that case you’ll need to run
	your Eclipse IDE on the JDK in order for all the feature of Java
	Mission Control to work as expected. Detailed installation
	instructions are linked off the Oracle Java Mission Control home
	page.
	</p>

	<h2>Using the JMX Console</h2>

	<p>If you are familiar with the JConsole utility in the JDK, you’ll
	find the Java Mission Control JXM Console easily accessible,
	providing you with a superset of the functionality. For a start, it
	lets you detect and connect to Java processes running either locally
	on your machine, or remotely, through the Java Discovery Protocol
	(JDP) or given a JMX agent URL.</p>
	<p>Once connected, the JMX console allows you to monitor and visualize
	the JMX data of the Java process, to take actions depending on the
	observed values triggering conditions, to store recorded data for
	later analysis, and, of course, to load it back into Java Mission
	Control to take a deeper look into the observed behavior.</p>
	<p>Typically, the JMX Console would be used to continuously monitor a
	running process, by observing a small set of data of interest like
	the CPU load or heap usage. Once a certain condition is met, the
	console could be configured to dump the Flight Recorder data, for
	example, for later evaluation.</p>

	<h2>The Java Flight Recorder</h2>

	<p>When something goes wrong unexpectedly, it’s very important to be
	able to find out the exact circumstances in order to track down the
	root cause of failure. The Java Flight Recorder can be thought of as
	such a tool for the HotSpot JVM - it efficiently records information
	about the JVM and its environment, for as long as it’s running. When
	something interesting happens, the recorded data can be dumped and
	stored for later, off-line analysis, or it can be simply stored on
	an ongoing basis. It has a low performance impact, less then 2% for
	typical Java applications, when collecting data and events.</p>

	<h2>Creating Flight Recordings</h2>

	<p>
	In order to create flight recordings, you have to explicitly enable
	the Java Flight Recorder in the HotSpot JVM you’d like to monitor by
	passing a few additional flags to it upon startup. For details,
	please consult the extensive Java Flight Recorder Runtime Guide
	available at <a target="_blank"
	href="http://docs.oracle.com/javase/7/docs/technotes/guides/jfr">http://docs.oracle.com/javase/7/docs/technotes/guides/jfr</a>.
	</p>
	<p>Recordings can be timed or continuous. Timed recordings run for a
	given amount of time, and stop automatically once the time is up.
	When you create a timed recording in Java Mission Control, it will
	be automatically stored, downloaded and loaded into the tool for
	analysis once the recording completes. Continuous recordings, on the
	other hand, run until they are stopped by the end user.</p>
	<p>While creating recordings directly from Java Mission Control is the
	easiest choice for developers, users who need more flexibility can
	use the jcmd command line tool, or pass command line flags to the
	HotSpot JVM to get the desired behavior.</p>

	<h2>Analyzing Flight Recordings</h2>

	<p>Once you load up a flight recording in Java Mission Control, you
	can look at a number of different areas like code, memory, threads,
	locks and I/O and analyze various aspects of runtime behavior of
	your application.</p>
	<p>For example, for CPU-bound applications, the code view in the user
	interface will let you drill down into hotspots of your application,
	and discover optimization opportunities. If you’re tuning the GC, or
	tracking down memory allocation issues, then you can use the memory
	view to get a detailed view on individual GC events, allocation
	sites, GC pauses, etc. You can visualize the latency profile of your
	application by looking at I/O and Threads views, and even drill down
	into a view representing individual events in the recording.</p>

	<h2>Summary</h2>

	<p>Fortunately, you don’t have to wait for Java 8 to try out Java
	Mission Control and Java Flight Recorder. If you’re curious about
	the Eclipse RCP based application in the Oracle JDK, as I hope you’d
	be, check out the jmc application in the bin directory, and give it
	a spin.</p>

	<h2>Resources</h2>
	<ul>
	<li><a target="_blank" href="http://download.oracle.com/technology/products/missioncontrol/updatesites/base/5.5.0/eclipse/">Oracle
	Java Mission Control home page</a></li>
	<li><a target="_blank"
	href="http://www.youtube.com/watch?v=WMEpRUgp9Y4">Demo video</a></li>
	<li><a target="_blank"
	href="https://forums.oracle.com/thread/2579717">FAQ</a></li>
	<li><a target="_blank" href="http://hirt.se/blog/?cat=3">Marcus
	Hirt’s blog</a></li>
	<li><a target="_blank"
	href="https://blogs.oracle.com/henrik/entry/oracles_jvm_strategy">Oracle’s
	JVM Strategy</a></li>
	<li><a target="_blank"
	href="http://openjdk.java.net/projects/jdk8/features">Planned JDK
	8 Features</a></li>
	</ul>

	<div class="bottomitem">
	<h3>About the Authors</h3>

	<div class="row">
	<div class="col-sm-12">
	<div class="row">
	<div class="col-sm-8">
	<img class="author-picture"
	src="/community/eclipse_newsletter/2014/january/images/DaliborTopic75.jpg"
	alt="dalibor topic" />
	</div>
	<div class="col-sm-16">
	<p class="author-name">
	Dalibor Topic<br />
	<a target="_blank" href="http://www.oracle.com/index.html">Oracle</a>
	</p>
	<ul class="author-link">
	<li><a target="_blank" href="http://robilad.livejournal.com/">Blog</a></li>
	<li><a target="_blank" href="https://twitter.com/robilad">Twitter</a></li>
	<!--<li><a target="_blank" href="https://plus.google.com/+IanSkerrett">Google +</a></li>
	$og-->
	</ul>
	</div>
	</div>
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