Problem occuring when extending classes coming from 2 signed JAR

Question

Hi everyone,
I have 2 signed jar called "base_signed.jar" and "extended_signed.jar" using keytool with a testing certificate generated at runtime. All goes well because with both signed JARs I can use the URLClassLoader without any java.security.AccessControlException exception.
But the first JAR contains abstract class B, the latter JAR contains a concrete class A.
The problem occurs when I try to instantiate some class A coming from "extended_signed.jar" using Class.forName("blablaclassA").newInstance() and occurs only if this class A extends some other abstract class B contained inside "base_signed.jar" .
Pratically if the class A is casted as its common JVM ancestor of B (JInternalFrame) all goes well, otherwise if I try to cast A using its direct ancestor B, I receive the following exception:
network: Connessione a http://www.orion.lan/~antares/it/weev/wipidea/plugins/MeteoradarArpavPlugin$7.class con proxy=DIRECT
Exception in thread "AWT-EventQueue-35" java.lang.ClassCastException: it.weev.wipidea.plugins.MeteoradarArpavPlugin cannot be cast to it.weev.wipidea.base.AWipideaPlugin
     at it.weev.wipidea.base.PluginLoader.loadNetworkPlugin(Unknown Source)
     at it.weev.wipidea.applet.WipideaApplet.loadPlugin(Unknown Source)
     at it.weev.wipidea.applet.WipideaApplet$1.actionPerformed(Unknown Source)
     at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
     at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
     at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
     at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
     at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
     at java.awt.Component.processMouseEvent(Unknown Source)
     at javax.swing.JComponent.processMouseEvent(Unknown Source)
     at java.awt.Component.processEvent(Unknown Source)
     at java.awt.Container.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)
network: Voce cache non trovata [url: http://www.orion.lan/~antares/it/weev/wipidea/base/PluginLoader.class, versione: null]
network: Connessione a http://www.orion.lan/~antares/it/weev/wipidea/base/PluginLoader.class con proxy=DIRECT
network: Voce cache non trovata [url: http://www.orion.lan/~antares/it/weev/wipidea/base/network-classpath.class, versione: null]
---The strange thing is that if I don't sign both JARs the class A is casted on B without any exception, could for security reason like hash or other? Ideally I need all JAR signed only because I plan to load classes from all over the net, but seems that URLClassLoader throws an AccessControlException when called.
Anyway just now I solve all using only the common JVM ancestor of A and B, but what could be the final solution?
Thanks, bye.

Answer 1

Hi Sean,
The file in question has been signed which causes issues in both OSB directly and in Eclipse when we do an import into that tool first.Can you let us know what issues you faced? Any errors? If yes, please post the same here.
Regards,
Anuj
Edited by: Anuj Dwivedi on Feb 23, 2011 9:10 PM