Author: markt
Date: Tue Dec 15 18:48:54 2009
New Revision: 890937
URL: http://svn.apache.org/viewvc?rev=890937&view=rev
Log:
Improve memory leak protection
Modified:
tomcat/tc6.0.x/trunk/STATUS.txt
tomcat/tc6.0.x/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
tomcat/tc6.0.x/trunk/java/org/apache/catalina/core/LocalStrings.properties
tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml
tomcat/tc6.0.x/trunk/webapps/docs/config/listeners.xml
Modified: tomcat/tc6.0.x/trunk/STATUS.txt
URL:
http://svn.apache.org/viewvc/tomcat/tc6.0.x/trunk/STATUS.txt?rev=890937&r1=890936&r2=890937&view=diff
==============================================================================
--- tomcat/tc6.0.x/trunk/STATUS.txt (original)
+++ tomcat/tc6.0.x/trunk/STATUS.txt Tue Dec 15 18:48:54 2009
@@ -291,11 +291,6 @@
-1:
+0: markt Combined patch needs to have 834047 removed and 881765 added
-* Improvements to memory leak prevention
- http://people.apache.org/~markt/patches/2009-11-10-leak-prevention.patch
- +1: markt, kkolinko, jim
- -1:
-
* Additional fix for https://issues.apache.org/bugzilla/show_bug.cgi?id=48097
1) Code cleanup: Remove use of WebappClassLoader$PrivilegedFindResource,
because all findResourceInternal(String,String) calls are now already
Modified:
tomcat/tc6.0.x/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
URL:
http://svn.apache.org/viewvc/tomcat/tc6.0.x/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java?rev=890937&r1=890936&r2=890937&view=diff
==============================================================================
---
tomcat/tc6.0.x/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
(original)
+++
tomcat/tc6.0.x/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
Tue Dec 15 18:48:54 2009
@@ -17,21 +17,64 @@
package org.apache.catalina.core;
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLConnection;
+
import javax.imageio.ImageIO;
import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleEvent;
import org.apache.catalina.LifecycleListener;
+import org.apache.juli.logging.Log;
+import org.apache.juli.logging.LogFactory;
+import org.apache.tomcat.util.res.StringManager;
/**
- * Provide a workaround for known places where the Java Runtime environment
uses
+ * Provide a workaround for known places where the Java Runtime environment can
+ * cause a memory leak or lock files.
+ * <p>
+ * Memory leaks occur when JRE code uses
* the context class loader to load a singleton as this will cause a memory
leak
* if a web application class loader happens to be the context class loader at
* the time. The work-around is to initialise these singletons when Tomcat's
* common class loader is the context class loader.
+ * <p>
+ * Locked files usually occur when a resource inside a JAR is accessed without
+ * first disabling Jar URL connection caching. The workaround is to disable
this
+ * caching by default.
*/
public class JreMemoryLeakPreventionListener implements LifecycleListener {
+ protected static final Log log =
+ LogFactory.getLog(JreMemoryLeakPreventionListener.class);
+ protected static final StringManager sm =
+ StringManager.getManager(Constants.Package);
+
+ /**
+ * Protect against the memory leak caused when the first call to
+ * <code>sun.awt.AppContext.getAppContext()</code> is triggered by a web
+ * application. Defaults to <code>true</code>.
+ */
+ protected boolean appContextProtection = true;
+ public boolean isAppContextProtection() { return appContextProtection; }
+ public void setAppContextProtection(boolean appContextProtection) {
+ this.appContextProtection = appContextProtection;
+ }
+
+ /**
+ * Protect against resources being read for JAR files and, as a
side-effect,
+ * the JAR file becoming locked. Note this disables caching for all
+ * {...@link URLConnection}s, regardless of type. Defaults to
+ * <code>true</code>.
+ */
+ protected boolean urlCacheProtection = true;
+ public boolean isUrlCacheProtection() { return urlCacheProtection; }
+ public void setUrlCacheProtection(boolean urlCacheProtection) {
+ this.urlCacheProtection = urlCacheProtection;
+ }
+
public void lifecycleEvent(LifecycleEvent event) {
// Initialise these classes when Tomcat starts
if (Lifecycle.INIT_EVENT.equals(event.getType())) {
@@ -41,7 +84,6 @@
*
* Those libraries / components known to trigger memory leaks due
to
* eventual calls to getAppContext() are:
- *
* - Google Web Toolkit via its use of javax.imageio
* - Tomcat via its use of java.beans.Introspector.flushCaches() in
* 1.6.0_15 onwards
@@ -51,8 +93,37 @@
// Trigger a call to sun.awt.AppContext.getAppContext(). This will
// pin the common class loader in memory but that shouldn't be an
// issue.
- ImageIO.getCacheDirectory();
+ if (appContextProtection) {
+ ImageIO.getCacheDirectory();
+ }
+
+ /*
+ * Several components end up opening JarURLConnections without
first
+ * disabling caching. This effectively locks the file. Whilst more
+ * noticeable and harder to ignore on Windows, it affects all
+ * operating systems.
+ *
+ * Those libraries/components known to trigger this issue include:
+ * - log4j versions 1.2.15 and earlier
+ * - javax.xml.bind.JAXBContext.newInstance()
+ */
+ // Set the default URL caching policy to not to cache
+ if (urlCacheProtection) {
+ try {
+ // Doesn't matter that this JAR doesn't exist - just as
long as
+ // the URL is well-formed
+ URL url = new URL("jar:file://dummy.jar!/");
+ URLConnection uConn = url.openConnection();
+ uConn.setDefaultUseCaches(false);
+ } catch (MalformedURLException e) {
+ log.error(sm.getString(
+ "jreLeakListener.jarUrlConnCacheFail"), e);
+ } catch (IOException e) {
+ log.error(sm.getString(
+ "jreLeakListener.jarUrlConnCacheFail"), e);
+ }
+ }
}
}
Modified:
tomcat/tc6.0.x/trunk/java/org/apache/catalina/core/LocalStrings.properties
URL:
http://svn.apache.org/viewvc/tomcat/tc6.0.x/trunk/java/org/apache/catalina/core/LocalStrings.properties?rev=890937&r1=890936&r2=890937&view=diff
==============================================================================
--- tomcat/tc6.0.x/trunk/java/org/apache/catalina/core/LocalStrings.properties
(original)
+++ tomcat/tc6.0.x/trunk/java/org/apache/catalina/core/LocalStrings.properties
Tue Dec 15 18:48:54 2009
@@ -59,6 +59,7 @@
httpHostMapper.container=This container is not a StandardHost
interceptorValve.alreadyStarted=InterceptorValve has already been started
interceptorValve.notStarted=InterceptorValve has not yet been started
+jreLeakListener.jarUrlConnCacheFail=Failed to disable Jar URL connection
caching by default
naming.wsdlFailed=Failed to find wsdl file: {0}
naming.bindFailed=Failed to bind object: {0}
naming.jmxRegistrationFailed=Failed to register in JMX: {0}
Modified: tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml
URL:
http://svn.apache.org/viewvc/tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml?rev=890937&r1=890936&r2=890937&view=diff
==============================================================================
--- tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml (original)
+++ tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml Tue Dec 15 18:48:54 2009
@@ -259,7 +259,8 @@
</fix>
<fix>
Provide a new listener to protect against a memory leak caused by a
- change in the Sun JRE from version 1.6.0_15 onwards. (markt)
+ change in the Sun JRE from version 1.6.0_15 onwards. Also include
+ protection against locked JAR files. (markt)
</fix>
<fix>
Don't swallow exceptions in ApplicationContextFacade.doPrivileged()
Modified: tomcat/tc6.0.x/trunk/webapps/docs/config/listeners.xml
URL:
http://svn.apache.org/viewvc/tomcat/tc6.0.x/trunk/webapps/docs/config/listeners.xml?rev=890937&r1=890936&r2=890937&view=diff
==============================================================================
--- tomcat/tc6.0.x/trunk/webapps/docs/config/listeners.xml (original)
+++ tomcat/tc6.0.x/trunk/webapps/docs/config/listeners.xml Tue Dec 15 18:48:54
2009
@@ -227,19 +227,36 @@
leak if a web application class loader happens to be the context class
loader at the time. The work-around is to initialise these singletons when
this listener starts as Tomcat's common class loader is the context class
- loader at that time.</p>
+ loader at that time. It also provides work-arounds for known issues that
+ can result in locked JAR files.</p>
- <p>Currently the <strong>JRE Memory Leak Prevention Listener</strong>
- provides work-arounds for the following:</p>
- <ul>
- <li><code>sun.awt.AppContext.getAppContext()</code></li>
- </ul>
-
<p>This listener must only be nested within <a
href="server.html">Server</a>
elements.</p>
- <p>No additional attributes are supported by the <strong>JRE Memory Leak
- Prevention Listener</strong>.</p>
+ <p>The following additional attributes are supported by the <strong>JRE
+ Memory Leak Prevention Listener</strong>:</p>
+
+ <attributes>
+
+ <attribute name="appContextProtection" required="false">
+ <p>Enables protection so that calls to
+ <code>sun.awt.AppContext.getAppContext()</code> triggered by a web
+ application do not result in a memory leak. Note that a call to this
+ method will be triggered as part of the web application stop process so
+ it is strongly recommended that this protection is enabled. The default
+ is <code>true</code></p>
+ </attribute>
+
+ <attribute name="urlCacheProtection" required="false">
+ <p>Enables protection so that reading resources from JAR files using
+ <code>java.net.URLConnection</code>s does not result in the JAR file
+ being locked. Note that enabling this protection disables caching by
+ default for all resources obtained via
+ <code>java.net.URLConnection</code>s. Caching may be re-enabled on a
+ case by case basis as required. Defaults to <code>true</code>.</p>
+ </attribute>
+
+ </attributes>
</subsection>
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