无法关闭 java.exe，JNI 调用

Question

I am using a proprietary dll using the jni, anyway i need to free resources manually on shutdown. I tried using shutdownhooks but if i dont call my method for freeing these resources which happens on killing java through netbeans or per taskmanager, java.exe is staying alive. I cant even kill it with the taskmanager (access denied). Is there another safe method for making sure that a free resource method is called after processkill or other unsafe exiting?

Edit:

Thanks for the first answer but it does not solve my problem. If i kill the program during the sleep call, it wont shutdown properly. But if i wait this 5 seconds, it is properly shutting down.

I think the call "AdsCallDllFunction.adsPortOpen()" is registering something for cleanup and if the process is killed, java.exe stays for about 5 - 10 minutes alive until the jvm dies.

    import de.beckhoff.jni.tcads.AdsCallDllFunction;
    import de.beckhoff.jni.tcads.AdsVersion;

    /**
     *
     * @author Christian
     */
    public class KillTest {

        /**
         * @param args the command line arguments
         */
        public static void main(String[] args) {
            long port = 0;

            if (port == 0) {
                AdsVersion lAdsVersion = null;
                port = AdsCallDllFunction.adsPortOpen();

            }
            System.out.println("runs through this");
            /**
             * If i call the following function, it can exit.
             **/
            //AdsCallDllFunction.adsPortClose();
            try {
             /**
             * If i kill the program during this sleep call, it wont exit for a timespan of 5-10 minutes
             */
                Thread.sleep(5000);
            } catch (InterruptedException ex) {

            }



            System.exit(0);
        }

    }

Edit 2:

http://i.stack.imgur.com/4Vh71.png

For own research you can download twincat 3 on http://www.beckhoff.com/ . The DLL and jar file is provided in C:\\TwinCAT\\AdsApi\\AdsToJava.

I think that the dll tries to communicate with the twincat 3 driver which gets installed on twincat 3 setup. However if u try to kill java during the 5 seconds sleeptime through the taskmanager, the program gets stuck.

Answer 1

As of Java 7, you can use try-with-resources statement, for ensuring that each used (opened) resource that needs to finally be closed, is closed at the end of the statement. For more information, look here: http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html