Applet has java.lang.Runtime.addShutdownHook exception - want to avoid ICE setup

[Jon S]

Hello,

Applet failure I call my method Z.createConnection and I will get an exception with "java.lang.Runtime.addShutdownHook". This is all realted to java.security.AccessControlException: access denied (java.lang.RuntimePermission shutdownHooks) which is triggered by an Ice call.

Is there any way to disable the shutdown hook setup? ( note - signing the JAR or using JNLP is not an option for me ).

Do I have to hack the code or is there some method to call to prevent the Ice.Application.changeHook(...) call.

public class Z extends Ice.Application
{
    public void createConnection()
    {
        String[] custArgs = new String[7];
        custArgs[0] = "--Ice.MessageSizeMax=16384"; // 16 mega-bytes
        custArgs[1] = "--Ice.BatchAutoFlush=1";
        custArgs[2] = "--Ice.ACM.Client=0";
        custArgs[3] = "--Ice.ThreadPool.Client.Size=1";
        custArgs[4] = "--Ice.ThreadPool.Client.SizeMax=15";
        custArgs[5] = "--Ice.ThreadPool.Server.Size=1";
        custArgs[6] = "--Ice.ThreadPool.Server.SizeMax=15";

        int status = main("CROME", custArgs);
    }
}

I get the following message:

network: Connecting http://binky.quantumsi.com/jbin/Zcheck?cmd=header with cookie "__utma=121695755.852096886.1270944348.1270944348.1270944348.1"
!! 6/6/11 16:29:04:074 CROME: error: Thread-18: unknown exception: java.security.AccessControlException: access denied (java.lang.RuntimePermission shutdownHooks)
       at java.security.AccessControlContext.checkPermission(Unknown Source)
       at java.security.AccessController.checkPermission(Unknown Source)
       at java.lang.SecurityManager.checkPermission(Unknown Source)
       at java.lang.Runtime.addShutdownHook(Unknown Source)
       at Ice.Application.changeHook(Application.java:498)
       at Ice.Application.destroyOnInterrupt(Application.java:348)
       at Ice.Application.doMain(Application.java:197)
       at Ice.Application.main(Application.java:180)
       at Ice.Application.main(Application.java:71)
       at Z.createConnection(BRXE)
       at Z.init(BRXE)
       at Zmain.run(BRXE)

Thanks in Advance

Jon

[xdm]

You can call the overload of Application that receive a SignalPolicy with SignalPolicy.NoSignalHandling this will avoid the setup of the shutdown hook. But Ice.Application isn't interesting for Applets as isn't designed to work with the applet life cycle "start/init/stop/destroy".

For a complete applet demo see java/demo/Ice/applet in Ice distribution. This demo shows how to integrate the Ice run time, with the applet life cycle.

[Jon S]

Thanks xdm,

The below seems to have worked for me, e.g. using Ice.Application with a basic Applet

import Ice.SignalPolicy;

public class Z extends Ice.Application
{
    public Z() {
        // Do this only if using an unsigned applet, JNLP and signed applets
        // can and should handle a shutdown hook. Since this mode is
        // "read-only' I am not concerned about 'bad' items like file
        // and/or database corruption.
        super(SignalPolicy.NoSignalHandling);
    }

    // other code/methods removed here ....
}

The overload of Application that receive a SignalPolicy with SignalPolicy.NoSignalHandling did avoid the shutdown hook issue.

I understand your comment But Ice.Application isn't interesting for Applets as isn't designed to work with the applet life cycle "start/init/stop/destroy". but this solved an immediate issue with minimal code changes.

As per your direction I will inspect the applet demo see java/demo/Ice/applet in Ice distribution which you state shows how to integrate the Ice run time, with the applet life cycle. IMHO I think this will be much more inline with my intended use case.

Thanks for the prompt pointer to the solution

Jon S.