Author: markt
Date: Wed Nov 18 12:25:41 2009
New Revision: 881748
URL: http://svn.apache.org/viewvc?rev=881748&view=rev
Log:
Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=44041
Threading issue in class loading
Modified:
tomcat/tc6.0.x/trunk/STATUS.txt
tomcat/tc6.0.x/trunk/java/org/apache/catalina/loader/WebappClassLoader.java
tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml
Modified: tomcat/tc6.0.x/trunk/STATUS.txt
URL:
http://svn.apache.org/viewvc/tomcat/tc6.0.x/trunk/STATUS.txt?rev=881748&r1=881747&r2=881748&view=diff
==============================================================================
--- tomcat/tc6.0.x/trunk/STATUS.txt (original)
+++ tomcat/tc6.0.x/trunk/STATUS.txt Wed Nov 18 12:25:41 2009
@@ -142,13 +142,6 @@
+1: markt
-1:
-* Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=44041
- Threading issue in classloading. Adds a sync so please check performance
- Updated to use Filip's suggestion
- http://people.apache.org/~markt/patches/2009-11-05-bug44041.patch
- +1: markt, fhanik, kkolinko
- -1:
-
* Allow per instance configuration of JULI or log4j for core Tomcat logging
Updated patch with the suggested tweak for 6.0.x so we don't break Eclipse
integration
Modified:
tomcat/tc6.0.x/trunk/java/org/apache/catalina/loader/WebappClassLoader.java
URL:
http://svn.apache.org/viewvc/tomcat/tc6.0.x/trunk/java/org/apache/catalina/loader/WebappClassLoader.java?rev=881748&r1=881747&r2=881748&view=diff
==============================================================================
--- tomcat/tc6.0.x/trunk/java/org/apache/catalina/loader/WebappClassLoader.java
(original)
+++ tomcat/tc6.0.x/trunk/java/org/apache/catalina/loader/WebappClassLoader.java
Wed Nov 18 12:25:41 2009
@@ -1296,118 +1296,99 @@
public Class loadClass(String name, boolean resolve)
throws ClassNotFoundException {
- if (log.isDebugEnabled())
- log.debug("loadClass(" + name + ", " + resolve + ")");
- Class clazz = null;
-
- // Log access to stopped classloader
- if (!started) {
- try {
- throw new IllegalStateException();
- } catch (IllegalStateException e) {
- log.info(sm.getString("webappClassLoader.stopped", name), e);
- }
- }
-
- // (0) Check our previously loaded local class cache
- clazz = findLoadedClass0(name);
- if (clazz != null) {
- if (log.isDebugEnabled())
- log.debug(" Returning class from cache");
- if (resolve)
- resolveClass(clazz);
- return (clazz);
- }
-
- // (0.1) Check our previously loaded class cache
- clazz = findLoadedClass(name);
- if (clazz != null) {
+ synchronized (name.intern()) {
if (log.isDebugEnabled())
- log.debug(" Returning class from cache");
- if (resolve)
- resolveClass(clazz);
- return (clazz);
- }
-
- // (0.2) Try loading the class with the system class loader, to prevent
- // the webapp from overriding J2SE classes
- try {
- clazz = system.loadClass(name);
+ log.debug("loadClass(" + name + ", " + resolve + ")");
+ Class clazz = null;
+
+ // Log access to stopped classloader
+ if (!started) {
+ try {
+ throw new IllegalStateException();
+ } catch (IllegalStateException e) {
+ log.info(sm.getString("webappClassLoader.stopped", name),
e);
+ }
+ }
+
+ // (0) Check our previously loaded local class cache
+ clazz = findLoadedClass0(name);
if (clazz != null) {
+ if (log.isDebugEnabled())
+ log.debug(" Returning class from cache");
if (resolve)
resolveClass(clazz);
return (clazz);
}
- } catch (ClassNotFoundException e) {
- // Ignore
- }
-
- // (0.5) Permission to access this class when using a SecurityManager
- if (securityManager != null) {
- int i = name.lastIndexOf('.');
- if (i >= 0) {
- try {
- securityManager.checkPackageAccess(name.substring(0,i));
- } catch (SecurityException se) {
- String error = "Security Violation, attempt to use " +
- "Restricted Class: " + name;
- log.info(error, se);
- throw new ClassNotFoundException(error, se);
- }
+
+ // (0.1) Check our previously loaded class cache
+ clazz = findLoadedClass(name);
+ if (clazz != null) {
+ if (log.isDebugEnabled())
+ log.debug(" Returning class from cache");
+ if (resolve)
+ resolveClass(clazz);
+ return (clazz);
}
- }
-
- boolean delegateLoad = delegate || filter(name);
-
- // (1) Delegate to our parent if requested
- if (delegateLoad) {
- if (log.isDebugEnabled())
- log.debug(" Delegating to parent classloader1 " + parent);
- ClassLoader loader = parent;
- if (loader == null)
- loader = system;
+
+ // (0.2) Try loading the class with the system class loader, to
prevent
+ // the webapp from overriding J2SE classes
try {
- clazz = loader.loadClass(name);
+ clazz = system.loadClass(name);
if (clazz != null) {
- if (log.isDebugEnabled())
- log.debug(" Loading class from parent");
if (resolve)
resolveClass(clazz);
return (clazz);
}
} catch (ClassNotFoundException e) {
- ;
+ // Ignore
}
- }
-
- // (2) Search local repositories
- if (log.isDebugEnabled())
- log.debug(" Searching local repositories");
- try {
- clazz = findClass(name);
- if (clazz != null) {
+
+ // (0.5) Permission to access this class when using a
SecurityManager
+ if (securityManager != null) {
+ int i = name.lastIndexOf('.');
+ if (i >= 0) {
+ try {
+
securityManager.checkPackageAccess(name.substring(0,i));
+ } catch (SecurityException se) {
+ String error = "Security Violation, attempt to use " +
+ "Restricted Class: " + name;
+ log.info(error, se);
+ throw new ClassNotFoundException(error, se);
+ }
+ }
+ }
+
+ boolean delegateLoad = delegate || filter(name);
+
+ // (1) Delegate to our parent if requested
+ if (delegateLoad) {
if (log.isDebugEnabled())
- log.debug(" Loading class from local repository");
- if (resolve)
- resolveClass(clazz);
- return (clazz);
+ log.debug(" Delegating to parent classloader1 " + parent);
+ ClassLoader loader = parent;
+ if (loader == null)
+ loader = system;
+ try {
+ clazz = loader.loadClass(name);
+ if (clazz != null) {
+ if (log.isDebugEnabled())
+ log.debug(" Loading class from parent");
+ if (resolve)
+ resolveClass(clazz);
+ return (clazz);
+ }
+ } catch (ClassNotFoundException e) {
+ ;
+ }
}
- } catch (ClassNotFoundException e) {
- ;
- }
-
- // (3) Delegate to parent unconditionally
- if (!delegateLoad) {
+
+ // (2) Search local repositories
if (log.isDebugEnabled())
- log.debug(" Delegating to parent classloader at end: " +
parent);
- ClassLoader loader = parent;
- if (loader == null)
- loader = system;
+ log.debug(" Searching local repositories");
try {
- clazz = loader.loadClass(name);
+ clazz = findClass(name);
if (clazz != null) {
if (log.isDebugEnabled())
- log.debug(" Loading class from parent");
+ log.debug(" Loading class from local repository");
if (resolve)
resolveClass(clazz);
return (clazz);
@@ -1415,9 +1396,30 @@
} catch (ClassNotFoundException e) {
;
}
+
+ // (3) Delegate to parent unconditionally
+ if (!delegateLoad) {
+ if (log.isDebugEnabled())
+ log.debug(" Delegating to parent classloader at end: " +
parent);
+ ClassLoader loader = parent;
+ if (loader == null)
+ loader = system;
+ try {
+ clazz = loader.loadClass(name);
+ if (clazz != null) {
+ if (log.isDebugEnabled())
+ log.debug(" Loading class from parent");
+ if (resolve)
+ resolveClass(clazz);
+ return (clazz);
+ }
+ } catch (ClassNotFoundException e) {
+ ;
+ }
+ }
+
+ throw new ClassNotFoundException(name);
}
-
- throw new ClassNotFoundException(name);
}
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=881748&r1=881747&r2=881748&view=diff
==============================================================================
--- tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml (original)
+++ tomcat/tc6.0.x/trunk/webapps/docs/changelog.xml Wed Nov 18 12:25:41 2009
@@ -81,6 +81,10 @@
persistent session manager. (markt)
</fix>
<fix>
+ <bug>44041</bug>: Fix threading issue in WebappClassLoader that can
lead
+ to duplicate class definition under high load. (markt/fhanik)
+ </fix>
+ <fix>
<bug>44943</bug>: Use the same engine name in server.xml comments to
reduce copy and pastes issues. (markt, kkolinko)
</fix>
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