GUI线程作业不是从callable调用的(GUI Thread job is not called from callable)

 我试图从可调用的更新UI，但失败。 为什么是System.out.println("UI thread."); 从未打电话？ 我正在使用SWT。 
 
Callable<Boolean> callable = new Callable<Boolean>() {
    @Override
    public Boolean call() throws Exception {
        System.out.println("Executing Callable.");

        Display.getDefault().asyncExec(new Runnable() {
            @Override
            public void run() {
                System.out.println("UI thread.");
            }
        });

        System.out.println("End.");
        return true;
    }
};

ExecutorService executor = Executors.newFixedThreadPool(10);
executor.submit(callable);

I am trying to update the UI from a callable, but fail. Why is the System.out.println("UI thread."); never called? I am using SWT.
 
Callable<Boolean> callable = new Callable<Boolean>() {
    @Override
    public Boolean call() throws Exception {
        System.out.println("Executing Callable.");

        Display.getDefault().asyncExec(new Runnable() {
            @Override
            public void run() {
                System.out.println("UI thread.");
            }
        });

        System.out.println("End.");
        return true;
    }
};

ExecutorService executor = Executors.newFixedThreadPool(10);
executor.submit(callable);

原文：https://stackoverflow.com/questions/14646450