java - Allow System.exit only for certain classes

Question

We are having a Java 1.7 application, that supports plugins, which customers can program in Java. We want to restrict the plugins however from calling System.exit. We can do this via a SecurityManager. However, in the core application there are rare situation when we want to call System.exit. Is there a way to exclude classes or packages from a SecurityManager?

Answer 1

Similar to Batty's answer except you can disable setting the security manager again and override the checkExit() method. What I would do is allow calls to System.exit() but this should trigger the plugin to stop/unload rather than exit the whole JVM.

You can use a Thread.currentThread().getStackTrace() to work out which code called the System.exit();

Answer 2

I think you are looking for this :

private static class ExitTrappedException extends SecurityException 
{ 
} 
private static void forbidSystemExitCall()
{ 
    final SecurityManager securityManager = new SecurityManager() { 
         public void checkPermission( Permission permission ) 
        { 
              if( "exitVM".equals( permission.getName() ) ) 
            {  
                    throw new ExitTrappedException() ; 
            }
        }
    } ; 
    System.setSecurityManager( securityManager ) ; 
} 

private static void enableSystemExitCall() 
{  
       System.setSecurityManager( null ) ; 
}

This is inside your class from which plugin is invoked.

put you plugin call between forbidSystemExitCall and enableSystemExitCall.