Index: core/src/org/netbeans/core/NbTopManager.java
===================================================================
RCS file: /cvs/core/src/org/netbeans/core/NbTopManager.java,v
retrieving revision 1.122
diff -u -t -r1.122 NbTopManager.java
--- core/src/org/netbeans/core/NbTopManager.java	5 Oct 2001 16:01:40 -0000	1.122
+++ core/src/org/netbeans/core/NbTopManager.java	10 Oct 2001 13:59:24 -0000
@@ -755,7 +755,8 @@
     public ClassLoader systemClassLoader () {
         ModuleSystem ms = getModuleSystem();
         if (ms != null) {
-            return ms.getManager().getClassLoader();
+            // #16265: do not go straight to ModuleManager
+            return ms.getSystemClassLoader();
         } else {
             // This can be called very early: if lookup asks for ClassLoader.
             // For now, just give the startup classloader.
Index: core/src/org/netbeans/core/modules/ModuleSystem.java
===================================================================
RCS file: /cvs/core/src/org/netbeans/core/modules/ModuleSystem.java,v
retrieving revision 1.10
diff -u -t -r1.10 ModuleSystem.java
--- core/src/org/netbeans/core/modules/ModuleSystem.java	20 Jul 2001 18:12:50 -0000	1.10
+++ core/src/org/netbeans/core/modules/ModuleSystem.java	10 Oct 2001 13:59:25 -0000
@@ -114,31 +114,50 @@
     /** Get the system classloader, for use from NbTopManager.
      * When it changes, NbTopManager will likewise be notified.
      */
-    public ClassLoader getSystemClassLoader() {
-        if (! addedClassLoaderListener) {
-            addedClassLoaderListener = true;
+    public synchronized ClassLoader getSystemClassLoader() {
+        if (systemClassLoader == null) {
+            // First time this has been called. Set to dummy and change later.
+            systemClassLoader = ModuleSystem.class.getClassLoader();
+            // Check for future changes.
             class ListenerFirer implements PropertyChangeListener, Runnable {
+                // do not fire too frequently:
+                private boolean needToChange = true;
                 public void propertyChange(PropertyChangeEvent ev) {
                     if (ModuleManager.PROP_CLASS_LOADER.equals(ev.getPropertyName())) {
-                        // Exit read mutex first for safety.
+                        // Get the new one in a write mutex.
+                        needToChange = true;
                         RequestProcessor.postRequest(ListenerFirer.this);
                     }
                 }
                 public void run() {
-                    NbTopManager.get().fireSystemClassLoaderChange();
-                    Util.err.log("fired change in system classloader");
+                    if (needToChange) {
+                        needToChange = false;
+                        // We got the change, now in write mutex get the new one.
+                        ClassLoader nue;
+                        mgr.mutexPrivileged().enterWriteAccess();
+                        try {
+                            nue = mgr.getClassLoader();
+                        } finally {
+                            mgr.mutexPrivileged().exitWriteAccess();
+                        }
+                        synchronized (ModuleSystem.this) {
+                            systemClassLoader = nue;
+                        }
+                        NbTopManager.get().fireSystemClassLoaderChange();
+                        Util.err.log("fired change in system classloader");
+                    }
                 }
             }
-            mgr.addPropertyChangeListener(new ListenerFirer());
-        }
-        mgr.mutexPrivileged().enterWriteAccess();
-        try {
-            return mgr.getClassLoader();
-        } finally {
-            mgr.mutexPrivileged().exitWriteAccess();
+            ListenerFirer lf = new ListenerFirer();
+            mgr.addPropertyChangeListener(lf);
+            // Also change ASAP to the real thing.
+            RequestProcessor.postRequest(lf);
         }
+        return systemClassLoader;
     }
-    private boolean addedClassLoaderListener = false;
+    // #16265: keep a local copy so that every call does not have to
+    // enter the write mutex.
+    private ClassLoader systemClassLoader = null;
     
     /** Produce a list of JAR files including all installed modules,
      * their extensions, and enabled locale variants of both.