Run Java Threads sequentially

java multithreading concurrency java.util.concurrent
Geek picture Geek · Mar 28, 2011 · Viewed 27.2k times · Source

How will you execute Three threads sequentially? For eg. Thread1, Thread2, Thread3. It is not possible to pass the reference of one Thread to the other and invoke from the run() method.

So code should be like this:

 Thread1.start();
 Thread2.start();
 Thread3.start();

and out put should be

 Printing Thread1
 Printing Thread2
 Printing Thread3

This can be possible by using ThreadPoolExecutor and using a blocking queue but even that is not an acceptable answer.

Answer

pajton picture pajton · Mar 28, 2011

You could use Executors.newSingleThreadExecutor(), but strictly speaking this launches only one Thread, so may not be expected solution.

The simpliest solution using just Thread class:

Thread1.start();
Thread1.join();
Thread2.start();
Thread2.join();
Thread3.start();
Thread3.join();

(I omitted exception handling for clarity, Thread.join() can throw InterruptedException)

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