Oracle Forms crashes when trying to open form - oracleforms

Question

Oracle forms crashes when I'm trying to open a form in my local forms environment. This was earlier working for me but I did start to get this error after I have re-install my forms environment. The forms is also working as it should on the server. I get the following error in the Java console:
Exception in thread "AWT-EventQueue-2" java.lang.NoClassDefFoundError: oracle/bali/share/sort/StringComparator
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
at java.lang.Class.getDeclaredMethod(Unknown Source)
at java.awt.Component.isCoalesceEventsOverriden(Unknown Source)
at java.awt.Component.isCoalesceEventsOverriden(Unknown Source)
at java.awt.Component.access$500(Unknown Source)
at java.awt.Component$3.run(Unknown Source)
at java.awt.Component$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.awt.Component.checkCoalescing(Unknown Source)
at java.awt.Component.<init>(Unknown Source)
at java.awt.Container.<init>(Unknown Source)
at oracle.ewt.lwAWT.LWComponent.<init>(Unknown Source)
at oracle.ewt.lwAWT.LWDataSourceChoice.<init>(Unknown Source)
at oracle.ewt.lwAWT.LWChoice.<init>(Unknown Source)
at oracle.ewt.comboBox.ComboBox.<init>(Unknown Source)
at oracle.ewt.comboBox.ComboBox.<init>(Unknown Source)
at oracle.forms.ui.VComboBox.<init>(Unknown Source)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at oracle.forms.handler.UICommon.instantiate(Unknown Source)
at oracle.forms.handler.UICommon.onCreate(Unknown Source)
at oracle.forms.handler.PopListItem.onCreate(Unknown Source)
at oracle.forms.handler.ComboBoxItem.onCreate(Unknown Source)
at oracle.forms.engine.Runform.onCreateHandler(Unknown Source)
at oracle.forms.engine.Runform.processMessage(Unknown Source)
at oracle.forms.engine.Runform.processSet(Unknown Source)
at oracle.forms.engine.Runform.onMessageReal(Unknown Source)
at oracle.forms.engine.Runform.onMessage(Unknown Source)
at oracle.forms.engine.Runform.processEventEnd(Unknown Source)
at oracle.ewt.lwAWT.LWComponent.redispatchEvent(Unknown Source)
at oracle.ewt.lwAWT.LWComponent.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: oracle.bali.share.sort.StringComparator
at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
... 51 more
Caused by: java.io.IOException: open HTTP connection failed:http://virtualxp-64805:8889/forms/java/oracle/bali/share/sort/StringComparator.class
at sun.plugin2.applet.Applet2ClassLoader.getBytes(Unknown Source)
at sun.plugin2.applet.Applet2ClassLoader.access$000(Unknown Source)
at sun.plugin2.applet.Applet2ClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
... 55 more
I'm using Oracle Forms 10 release 2 and I'm running it in Windows XP Mode.

Answer 1

After much headache I did found out that this is caused by incompatibility between Oracle Forms 10 release 2 (10.1.2.0.2) and Java 6. The error occur when using the list item as a combo box. Fortunately there is a fix and that are to apply Oracle Developer Suite 10g Release 2 (10.1.2) Patch Set 3 (10.1.2.3.0) on the local Oracle Home. Unfortunately this is not listed on the forms download site and therefore easy to miss.