Java Wait for thread to finish

Thread has a method that does that for you join which will block until the thread has finished executing.

You could use a CountDownLatch from the java.util.concurrent package. It is very useful when waiting for one or more threads to complete before continuing execution in the awaiting thread.

For example, waiting for three tasks to complete:

CountDownLatch latch = new CountDownLatch(3);...latch.await(); // Wait for countdown

The other thread(s) then each call latch.countDown() when complete with the their tasks. Once the countdown is complete, three in this example, the execution will continue.

SwingWorker has doInBackground() which you can use to perform a task. You have the option to invoke get() and wait for the download to complete or you can override the done() method which will be invoked on the event dispatch thread once the SwingWorker completes.

The Swingworker has advantages to your current approach in that it has many of the features you are looking for so there is no need to reinvent the wheel. You are able to use the getProgress() and setProgress() methods as an alternative to an observer on the runnable for download progress. The done() method as I stated above is called after the worker finishes executing and is performed on the EDT, this allows you load the data after the download has completed.