encourage early GC

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@17832 71c3de6d-444a-0410-be80-ed276b4c234a

test/src/main/java/org/jvnet/hudson/test/HudsonTestCase.java

@@ -226,6 +226,12 @@ public abstract class HudsonTestCase extends TestCase {
         env.dispose();
         ExtensionList.clearLegacyInstances();
         DescriptorExtensionList.clearLegacyInstances();
+
+        // Hudson creates ClassLoaders for plugins that hold on to file descriptors of its jar files,
+        // but because there's no explicit dispose method on ClassLoader, they won't get GC-ed until
+        // at some later point, leading to possible file descriptor overflow. So encourage GC now.
+        // see http://bugs.sun.com/view_bug.do?bug_id=4950148
+        System.gc();
     }
 
     protected void runTest() throws Throwable {