plugins/org.eclipse.mat.ui.help/tasks/analyzingfinalizer.html - mat/org.eclipse.mat - Git at Google

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 <meta name="DC.Type" content="task"/>
 <meta name="DC.Title" content="Analyzing Finalizer"/>
 <meta name="copyright" content="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 v1.0 which accompanies this distribution, and is available at http://www.eclipse.org/legal/epl-v10.html " type="primary"/>
 <meta name="DC.Rights.Owner" content="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 v1.0 which accompanies this distribution, and is available at http://www.eclipse.org/legal/epl-v10.html " type="primary"/>
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 <title>Analyzing Finalizer</title>
 </head>
 <body id="task_analyzingfinalizer">


 	<h1 class="title topictitle1">Analyzing Finalizer</h1>


 	<div class="body taskbody">
 		<div class="section context">
 			<p class="p"> Finalizers are executed when the internal garbage collection
 				cleans up the objects. Since you have no control over the finalizer
 				execution, it is recommended not to use them. Because the memory can
 				only be released when the finalize method finished, long running
 				tasks in the finalizer can block the garbage collection. To get the
 				finalizers overview select Finalizer Overview Query from the query
 				list:</p>

 			<img class="image" src="../mimes/finalizers.png" alt="Finalizer overview menu option and report"/>
 			<p class="p">This query includes the following subqueries:</p>


 <div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" class="table" frame="border" border="1" rules="all">
 					<tbody class="tbody">
 						<tr class="row">
 							<td class="entry" valign="top">
 								<strong class="ph b">Finalizer in Processing</strong>
 							</td>

 							<td class="entry" valign="top">
 								<p class="p"> Extract object currently processed by Finalizer Thread. This
 									query return the currently processed object by the Finalizer
 									Thread if any. The returned object can be processed for one of
 									the following reasons:</p>

 								<ul class="ul">
 									<li class="li">it is blocking</li>

 									<li class="li">it is long running</li>

 									<li class="li">the finalizer queue was or is still full.</li>

 								</ul>

 								<p class="p"> Use the finalizer queue query to check the queue.</p>

 							</td>

 						</tr>

 						<tr class="row">
 							<td class="entry" valign="top">
 								<strong class="ph b">Ready for Finalizer Thread</strong>
 							</td>

 							<td class="entry" valign="top">
 								<p class="p"> This query shows the objects ready for finalization in their
 									processing order. Following reasons can cause a full finalizer
 									queue:</p>

 								<ul class="ul">
 									<li class="li"> The currently processed object is blocking or long running
 										(please use our finalizer in processing query to check).</li>

 									<li class="li"> The application made use of too many objects with
 										finalize() which are queued up in memory.</li>

 								</ul>

 								<p class="p">Note: On J9 JVM-based dumps (e.g. IBM Java, OpenJ9), this
 								   list shows objects waiting to be finalized and those
 								   which have already been finalized and are waiting to be
 								   garbage collected. This query does not provide a way to
 								   differentiate the two (because DTFJ doesn't), although you may
 								   be able to differentiate based on object fields
 								   (e.g. a "closed" boolean field, etc.).</p>

 								<p class="p"> Additionally a class-level summary of the objects is provided</p>

 							</td>

 						</tr>

 						<tr class="row">
 							<td class="entry" valign="top">
 								<strong class="ph b">Finalizer Thread</strong>
 							</td>

 							<td class="entry" valign="top"> This query shows the daemon thread which performs the
 								object finalizations.</td>

 						</tr>

 						<tr class="row">
 							<td class="entry" valign="top">
 								<strong class="ph b">Finalizer Thread Locals</strong>
 							</td>

 							<td class="entry" valign="top">
 								<p class="p">
 									This query shows the thread locals of the daemon thread that
 									performs the object finalizations. If there are any, this
 									indicates miss-use in at least one of the processed finalizers
 									(
 									<span class="keyword cmdname">finalize()</span>
 									implemented wrong) and might cause severe problems (e.g.
 									unreclaimed memory permanently hold by the finalizer thread or
 									finalizer processed under useless thread locals harming
 									application logic)
 								</p>

 							</td>

 						</tr>

 					</tbody>

 				</table>
 </div>

 		</div>

 	</div>


 </body>
 </html>
	<?xml version="1.0" encoding="UTF-8"?>
	<!DOCTYPE html
	PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
	<html xml:lang="en-us" lang="en-us">
	<head>
	<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
	<meta name="DC.Type" content="task"/>
	<meta name="DC.Title" content="Analyzing Finalizer"/>
	<meta name="copyright" content="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 v1.0 which accompanies this distribution, and is available at http://www.eclipse.org/legal/epl-v10.html " type="primary"/>
	<meta name="DC.Rights.Owner" content="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 v1.0 which accompanies this distribution, and is available at http://www.eclipse.org/legal/epl-v10.html " type="primary"/>
	<meta name="DC.Format" content="XHTML"/>
	<meta name="DC.Identifier" content="task_analyzingfinalizer"/>
	<meta name="DC.Language" content="en-us"/>
	<link rel="stylesheet" type="text/css" href="../styles/commonltr.css"/>
	<title>Analyzing Finalizer</title>
	</head>
	<body id="task_analyzingfinalizer">


	<h1 class="title topictitle1">Analyzing Finalizer</h1>



	<div class="body taskbody">
	<div class="section context">
	<p class="p"> Finalizers are executed when the internal garbage collection
	cleans up the objects. Since you have no control over the finalizer
	execution, it is recommended not to use them. Because the memory can
	only be released when the finalize method finished, long running
	tasks in the finalizer can block the garbage collection. To get the
	finalizers overview select Finalizer Overview Query from the query
	list:</p>

	<img class="image" src="../mimes/finalizers.png" alt="Finalizer overview menu option and report"/>
	<p class="p">This query includes the following subqueries:</p>


	<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" class="table" frame="border" border="1" rules="all">
	<tbody class="tbody">
	<tr class="row">
	<td class="entry" valign="top">
	<strong class="ph b">Finalizer in Processing</strong>
	</td>

	<td class="entry" valign="top">
	<p class="p"> Extract object currently processed by Finalizer Thread. This
	query return the currently processed object by the Finalizer
	Thread if any. The returned object can be processed for one of
	the following reasons:</p>

	<ul class="ul">
	<li class="li">it is blocking</li>

	<li class="li">it is long running</li>

	<li class="li">the finalizer queue was or is still full.</li>

	</ul>

	<p class="p"> Use the finalizer queue query to check the queue.</p>

	</td>

	</tr>

	<tr class="row">
	<td class="entry" valign="top">
	<strong class="ph b">Ready for Finalizer Thread</strong>
	</td>

	<td class="entry" valign="top">
	<p class="p"> This query shows the objects ready for finalization in their
	processing order. Following reasons can cause a full finalizer
	queue:</p>

	<ul class="ul">
	<li class="li"> The currently processed object is blocking or long running
	(please use our finalizer in processing query to check).</li>

	<li class="li"> The application made use of too many objects with
	finalize() which are queued up in memory.</li>

	</ul>

	<p class="p">Note: On J9 JVM-based dumps (e.g. IBM Java, OpenJ9), this
	list shows objects waiting to be finalized and those
	which have already been finalized and are waiting to be
	garbage collected. This query does not provide a way to
	differentiate the two (because DTFJ doesn't), although you may
	be able to differentiate based on object fields
	(e.g. a "closed" boolean field, etc.).</p>

	<p class="p"> Additionally a class-level summary of the objects is provided</p>

	</td>

	</tr>

	<tr class="row">
	<td class="entry" valign="top">
	<strong class="ph b">Finalizer Thread</strong>
	</td>

	<td class="entry" valign="top"> This query shows the daemon thread which performs the
	object finalizations.</td>

	</tr>

	<tr class="row">
	<td class="entry" valign="top">
	<strong class="ph b">Finalizer Thread Locals</strong>
	</td>

	<td class="entry" valign="top">
	<p class="p">
	This query shows the thread locals of the daemon thread that
	performs the object finalizations. If there are any, this
	indicates miss-use in at least one of the processed finalizers
	(
	<span class="keyword cmdname">finalize()</span>
	implemented wrong) and might cause severe problems (e.g.
	unreclaimed memory permanently hold by the finalizer thread or
	finalizer processed under useless thread locals harming
	application logic)
	</p>

	</td>

	</tr>

	</tbody>

	</table>
	</div>

	</div>

	</div>


	</body>
	</html>