Issue using two instances of Executor service one after the other?

Posted on 2011-10-12
Medium Priority
Last Modified: 2012-05-12
In my code, I have two instances of of Executor Service with cached thread pools.

For example,

I have my service calling the runner object which implements runnable. I call runProcess method twice in a row. My question is if this is if one service will interfere with the other service. I need the threads in each service to finish one after the other. Please let me know.

void runProcess(){

ExecutorService service = Executors.newCachedThreadPool();
TestRunner runner = new Runner(object obj);
//some code


Question by:pkrish80
LVL 86

Expert Comment

ID: 36954029
They shouldn't interfere with each other, but if your intention is simply to create two threads, why not just use ONE ExecutorService?

Author Comment

ID: 36956075
I need to create two services with multiple threads. Both the set of the threads will be processing different datasets. Will they run sequentially per code above?
LVL 10

Accepted Solution

gordon_vt02 earned 400 total points
ID: 36962082
There are two ways you can ensure the threads execute sequentially.  The first is to use a fixed-size thread pool with a single thread.  The easiest way to accomplish that is


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That Executor will run submitted jobs one at a time in the order they were received.

The second option is to use a Latch or other blocking mechanism to prevent the second thread from running until it is notified that the first thread has completed.  This approach adds a lot of usually unnecessary complexity and I'd recommend the SingleThreadExecutor if you truly need the tasks to run sequentially.

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