plugins/org.eclipse.mat.ui.help/tasks/analyzingclassloader.dita

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    SPDX-License-Identifier: EPL-2.0
   
    Contributors:
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        Andrew Johnson (IBM Corporation) - fixes
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<!DOCTYPE reference PUBLIC "-//OASIS//DTD DITA Reference//EN" "reference.dtd" >
<reference id="task_analyzingclassloader" xml:lang="en-us">
	<title>Analyze Class Loader</title>
	<shortdesc>
		Class loaders load classes into the memory of the JVM. When
		analyzing the heap, class loaders are very important for two reasons:
		First, applications typically load components using separate class
		loaders. Second, the loaded classes are usually stored in a separate space (e.g. the perm space)
		which can also be depleted.
	</shortdesc>
	<prolog>
		<copyright>
			<copyryear year=""></copyryear>
			<copyrholder>
				Copyright (c) 2008, 2010 SAP AG and others.
			    All rights reserved. This program and the accompanying materials
			    are made available under the terms of the Eclipse Public License 2.0
			    which accompanies this distribution, and is available at
			    https://www.eclipse.org/legal/epl-2.0/
			</copyrholder>
		</copyright>
	</prolog>
	
	<refbody>
		<section>
			<title>Class Loader Explorer</title>
			<p>
				To get an overview, run the
				<menucascade>
					<uicontrol>Query Browser</uicontrol>
					<uicontrol>Java Basics</uicontrol>
					<uicontrol>Class Loader Explorer</uicontrol>
				</menucascade>
				inspection on the heap dump.

				<ul>
					<li>The Memory Analyzer attaches a meaningful label to the class
						loader - in the case of OSGi bundles it is the bundle id. Looking
						out for duplicate entries!</li>
					<li>Next to the class loader name, the table contains the defined
						classes and the number of live instances. If one and the same
						component is loaded multiple times, the number of live instances
						can indicate which class loaders is more alive and which one
						should be garbage collected.</li>
				</ul>
			</p>

			<image href="analyzingclassloader_explorer.png">
				<alt>Class Loader Explorer</alt>
			</image>

			<p>
				Find more information in this blog posting:
				<xref format="html" scope="external"
					href="http://dev.eclipse.org/blogs/memoryanalyzer/2008/05/17/the-unknown-generation-perm/">The Unknown Generation: Perm</xref>
			</p>

		</section>
	</refbody>
</reference>