Author: markt
Date: Tue Dec  1 18:44:32 2009
New Revision: 885860

URL: http://svn.apache.org/viewvc?rev=885860&view=rev
Log:
More memory leak protection - this time for the GC Daemon thread.

Modified:
    
tomcat/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
    tomcat/trunk/java/org/apache/catalina/core/LocalStrings.properties
    tomcat/trunk/webapps/docs/config/listeners.xml

Modified: 
tomcat/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
URL: 
http://svn.apache.org/viewvc/tomcat/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java?rev=885860&r1=885859&r2=885860&view=diff
==============================================================================
--- 
tomcat/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java 
(original)
+++ 
tomcat/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java 
Tue Dec  1 18:44:32 2009
@@ -18,6 +18,8 @@
 package org.apache.catalina.core;
 
 import java.io.IOException;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLConnection;
@@ -80,7 +82,7 @@
     /**
      * XML parsing can pin a web application class loader in memory. This is
      * particularly nasty as profilers (at least YourKit and Eclispe MAT) don't
-     * idenitfy any GC roots related to this. 
+     * identify any GC roots related to this. 
      */
     private boolean xmlParsingProtection = true;
     public boolean isXmlParsingProtection() { return xmlParsingProtection; }
@@ -88,6 +90,19 @@
         this.xmlParsingProtection = xmlParsingProtection;
     }
     
+    /**
+     * Protect against the memory leak caused when the first call to
+     * <code>sun.misc.GC.requestLatency(long)</code> is triggered by a web
+     * application. This first call will start a GC Daemon thread with the
+     * thread's context class loader configured to be the web application class
+     * loader. Defaults to <code>true</code>.
+     */
+    private boolean gcDaemonProtection = true;
+    public boolean isGcDaemonProtection() { return gcDaemonProtection; }
+    public void setGcDaemonProtection(boolean gcDaemonProtection) {
+        this.gcDaemonProtection = gcDaemonProtection;
+    }
+    
     @Override
     public void lifecycleEvent(LifecycleEvent event) {
         // Initialise these classes when Tomcat starts
@@ -150,8 +165,36 @@
                 try {
                     factory.newDocumentBuilder();
                 } catch (ParserConfigurationException e) {
-                    log.error(sm.getString(
-                            "jreLeakListener.xmlParseFail"), e);
+                    log.error(sm.getString("jreLeakListener.xmlParseFail"), e);
+                }
+            }
+            
+            /*
+             * Several components end up calling:
+             * sun.misc.GC.requestLatency(long)
+             * 
+             * Those libraries / components known to trigger memory leaks due 
to
+             * eventual calls to requestLatency(long) are:
+             * - javax.management.remote.rmi.RMIConnectorServer.start()
+             */
+            if (gcDaemonProtection) {
+                try {
+                    Class<?> clazz = Class.forName("sun.misc.GC");
+                    Method method = clazz.getDeclaredMethod("requestLatency",
+                            new Class[] {long.class});
+                    method.invoke(null, Long.valueOf(3600000));
+                } catch (ClassNotFoundException e) {
+                    log.error(sm.getString("jreLeakListener.gcDaemonFail"), e);
+                } catch (SecurityException e) {
+                    log.error(sm.getString("jreLeakListener.gcDaemonFail"), e);
+                } catch (NoSuchMethodException e) {
+                    log.error(sm.getString("jreLeakListener.gcDaemonFail"), e);
+                } catch (IllegalArgumentException e) {
+                    log.error(sm.getString("jreLeakListener.gcDaemonFail"), e);
+                } catch (IllegalAccessException e) {
+                    log.error(sm.getString("jreLeakListener.gcDaemonFail"), e);
+                } catch (InvocationTargetException e) {
+                    log.error(sm.getString("jreLeakListener.gcDaemonFail"), e);
                 }
             }
         }

Modified: tomcat/trunk/java/org/apache/catalina/core/LocalStrings.properties
URL: 
http://svn.apache.org/viewvc/tomcat/trunk/java/org/apache/catalina/core/LocalStrings.properties?rev=885860&r1=885859&r2=885860&view=diff
==============================================================================
--- tomcat/trunk/java/org/apache/catalina/core/LocalStrings.properties 
(original)
+++ tomcat/trunk/java/org/apache/catalina/core/LocalStrings.properties Tue Dec  
1 18:44:32 2009
@@ -65,6 +65,7 @@
 httpHostMapper.container=This container is not a StandardHost
 interceptorValve.alreadyStarted=InterceptorValve has already been started
 interceptorValve.notStarted=InterceptorValve has not yet been started
+jreLeakListener.gcDaemonFail=Failed to trigger creation of the GC Daemon 
thread during Tomcat start to prevent possible memory leaks. This is expected 
on non-Sun JVMs.
 jreLeakListener.jarUrlConnCacheFail=Failed to disable Jar URL connection 
caching by default
 jreLeakListener.xmlParseFail=Error whilst attempting to prevent memory leaks 
during XML parsing
 naming.wsdlFailed=Failed to find wsdl file: {0}

Modified: tomcat/trunk/webapps/docs/config/listeners.xml
URL: 
http://svn.apache.org/viewvc/tomcat/trunk/webapps/docs/config/listeners.xml?rev=885860&r1=885859&r2=885860&view=diff
==============================================================================
--- tomcat/trunk/webapps/docs/config/listeners.xml (original)
+++ tomcat/trunk/webapps/docs/config/listeners.xml Tue Dec  1 18:44:32 2009
@@ -244,7 +244,17 @@
         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>
+        is <code>true</code>.</p>
+      </attribute>
+
+      <attribute name="gcDaemonProtection" required="false">
+        <p>Enables protection so that calls to
+        <code>sun.misc.GC.requestLatency(long)</code> triggered by a web
+        application do not result in a memory leak. Use of RMI is likely to
+        trigger a call to this method. A side effect of enabling this 
protection
+        is the creation of a thread named "GC Daemon". The protection is uses
+        reflection to access internal Sun classes and may generate errors on
+        startup on non-Sun JVMs. The default is <code>true</code>.</p>
       </attribute>
 
       <attribute name="urlCacheProtection" required="false">



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