working around a memory leak in commons-logging. And they don't even...

working around a memory leak in commons-logging. And they don't even acknowledge that it's a bug. Sigh.


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@2868 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/PluginManager.java

@@ -18,6 +18,8 @@ import java.util.Set;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
+import org.apache.commons.logging.LogFactory;
+
 /**
  * Manages {@link PluginWrapper}s.
  *
@@ -129,6 +131,9 @@ public final class PluginManager {
         for (PluginWrapper p : activePlugins) {
             p.stop();
         }
+        // Work around a bug in commons-logging.
+        // See http://www.szegedi.org/articles/memleak.html
+        LogFactory.release(uberClassLoader);
     }
 
     private final class UberClassLoader extends ClassLoader {

core/src/main/java/hudson/PluginWrapper.java

@@ -5,6 +5,7 @@ import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.Project;
 import org.apache.tools.ant.taskdefs.Expand;
 import org.apache.tools.ant.types.FileSet;
+import org.apache.commons.logging.LogFactory;
 import org.kohsuke.stapler.StaplerRequest;
 import org.kohsuke.stapler.StaplerResponse;
 
@@ -356,6 +357,9 @@ public final class PluginWrapper {
             System.err.println("Failed to shut down "+shortName);
             System.err.println(t);
         }
+        // Work around a bug in commons-logging.
+        // See http://www.szegedi.org/articles/memleak.html
+        LogFactory.release(classLoader);
     }
 
     /**

core/src/main/java/hudson/WebAppMain.java

@@ -32,6 +32,7 @@ import java.util.logging.Logger;
  * @author Kohsuke Kawaguchi
  */
 public class WebAppMain implements ServletContextListener {
+    private final RingBufferLogHandler handler = new RingBufferLogHandler();
 
     /**
      * Creates the sole instance of {@link Hudson} and register it to the {@link ServletContext}.
@@ -116,7 +117,6 @@ public class WebAppMain implements ServletContextListener {
      * Installs log handler to monitor all Hudson logs.
      */
     private void installLogger() {
-        RingBufferLogHandler handler = new RingBufferLogHandler();
         Hudson.logRecords = handler.getView();
         Logger.getLogger("hudson").addHandler(handler);
     }
@@ -168,5 +168,9 @@ public class WebAppMain implements ServletContextListener {
         Hudson instance = Hudson.getInstance();
         if(instance!=null)
             instance.cleanUp();
+
+        // Logger is in the system classloader, so if we don't do this
+        // the whole web app will never be undepoyed.
+        Logger.getLogger("hudson").removeHandler(handler);
     }
 }