java.lang.reflect.InvocationTargetException?

Question

I am working in an applet, when I use Eclipse to run it I don't have any problem but when I try to load the applet on my Internet Explorer browser, it gives me this error:

java.lang.reflect.InvocationTargetException

I don't know what to do and why is not working with my browser and yes with Eclipse.

Any idea?

I run it using appletviewer and the problem came when I pressed the Exit button, which I have to exit the game. It doesn't exit the game actually... now I am even more lost..

------------- stack trace

C:\Course Technology\src>appletviewer TestJAlienHunt.html
Exception in thread "AWT-EventQueue-1" java.security.AccessControlException: access denied ("java.lang.RuntimePermission" "exitVM.0")
    at java.security.AccessControlContext.checkPermission(AccessControlContext.java:366)
    at java.security.AccessController.checkPermission(AccessController.java:555)
    at java.lang.SecurityManager.checkPermission(SecurityManager.java:549)
    at java.lang.SecurityManager.checkExit(SecurityManager.java:761)
    at java.lang.Runtime.exit(Runtime.java:105)
    at java.lang.System.exit(System.java:960)
    at JAlienHunt.actionPerformed(JAlienHunt.java:97)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6505)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6270)
    at java.awt.Container.processEvent(Container.java:2229)
    at java.awt.Component.dispatchEventImpl(Component.java:4861)
    at java.awt.Container.dispatchEventImpl(Container.java:2287)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)

    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
    at java.awt.Container.dispatchEventImpl(Container.java:2273)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:703)
    at java.awt.EventQueue.access$000(EventQueue.java:102)
    at java.awt.EventQueue$3.run(EventQueue.java:662)
    at java.awt.EventQueue$3.run(EventQueue.java:660)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
    at java.awt.EventQueue$4.run(EventQueue.java:676)
    at java.awt.EventQueue$4.run(EventQueue.java:674)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:673)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThre ad.java:151)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)

    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)

    at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)

Answer 1

An applet is not allowed to call System.exit. Other applets made by other people may be using that JVM, after all.

In general, an applet "ends" when the user chooses to close or leave the page (which causes the applet's stop method to be called). The applet cannot decide on its own when its operation ends.

In theory, you could make your applet display a blank rectangle or something, but really, an "Exit" function simply doesn't make sense in an applet, and shouldn't be present to begin with.