How to deal future objects and wait calls

Question

Hi all,
How can I handle Future objects if the Callable object calls a wait() into the call() method? If the Callable object is waiting for something, the call Future.get() throws an IllegalMonitorStateException.
For example:
public class Test {
    private final ExecutorService POOL = Executors.newFixedThreadPool(1);
    private static Random r = new Random(System.nanoTime());  
    List<Callable> waiting = new ArrayList<Callable>(10);
    public Test() {
        Future[] res = new Future[10];
        for (int i = 0; i < 10; i++) {
                res[i] = execute();  
        synchronized (res) {
            for (int i = 0; i < 10; i++) {
                try {
                    System.err.println(res.get(10L, TimeUnit.MILLISECONDS));
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
} catch (TimeoutException e) {
POOL.shutdown();
System.err.println("size: " + waiting.size());
private Future<Integer> execute() {
return POOL.submit(new Executor());
* @param args
public static void main(String[] args) {
Test t = new Test();
private class Executor implements Callable<Integer> {
public Integer call() throws Exception {
Integer value = -1;
try {
value = r.nextInt();
waiting.add(this);
wait(2000);
} catch (InterruptedException e) {
// Thread.currentThread().interrupt();
waiting.remove(this);
return value;
The Object.notify() documentation says:
"This method should only be called by a thread that is the owner of this object's monitor. A thread becomes the owner of the object's monitor in one of three ways:
* By executing a synchronized instance method of that object.
* By executing the body of a synchronized statement that synchronizes on the object.
* For objects of type Class, by executing a synchronized static method of that class.",
so how can the main thread became the owner?

Answer 1

Hello,
HR objects are not supposed to be in the SPAU list during the upgrade. It might show though because of the coding error in note 519678. The error wrote entries of HR objects in the tabel SMODILOG which is not supposed to be.
You can try the solution in the note 519678 to remove the entries of HR objects in SMODILOG and after that they will no longer be shown in SPAU.
Regards,
Joe