It's startupFinished() -> init() is run in parallel with welcome screen init,
which slows down welcome screen display.
I suggest to delay the init() call (which is already performed asynchronously in
RP) by submitting a scheduled task to the RP, delayed by 1500ms (which should be
enough even on minimum hardware configuration.
The "fix" is really trivial:
--- src/org/netbeans/modules/javacore/JMManager.java    11 Aug 2006 14:04:27
-0000      1.118.2.4.2.4
+++ src/org/netbeans/modules/javacore/JMManager.java    24 Aug 2006 09:49:52 -0000
@@ -1440,7 +1440,7 @@
                 public void run() {
                     init();
                 }
-            });
+            }, 1500);
         }
     }