Java (Android) multi-threading process

I am not sure if this is what causes all the problems, but you are creating a lot of unnecessary threads.

You shoud replace

private class PingThread extends Thread {

with :

private class PingThread implements Runnable {

or (using a more adequate name) :

private class PingTask implements Runnable {

i.e. the tasks submited to Executors are not supposed to be thread themselves. It works, because a Thread implements Runnable, but you are wasting it.

Observation:

After creating and observing a independent java application (logs) using same code, I came to know the followings:

• Somehow android OS architecture and/or processor is limiting the number of threads.
• LinkedBlockingQueue holds tasks before they executed, so if we have a long queue later threads in queue will have to wait more.
• Increase/Dynamic corePoolSize and maxPoolSize is doing the same, they added threads in queue
• Application uses 4-6% of CPU so we can't say CPU is overloading or utilizing full application resources but when application goes into background (GUI or other related OS and/or application based threads may stop or interrupted) CPU uses drops to 0-3%.

Solution:

For 50 iterations and 10 inner creates 500 threads now i did two things:

• Increase Thread.sleep(millis) time with some calculation involves.
• Decrease number of threads for each iteration. I was creating 10 threads now Math.ceil((double) 10 / 3) = 3 so we have 3 sequential PingUtils.executePingRequest(pingRequest) for each thread i.e. 3 * 3 = 9 remains 1 so we will create a separate thread for last request. For each iteration instead of creating 10 threads now i am creating 4 threads.
• Using this approach now i have 200 threads instead of 500 which solves the issue.

Threads create a new unique object, while runnable allows all the threads to share one object. As such, you should not extend Thread when trying to multithread, instead use Runnable:

class RunnableDemo implements Runnable {    private Thread thread;    String threadName="My thread";    public void run() {        //do your code from here 'logic'        System.out.println("Threading is Running");        try {            for(int i = 4; i > 0; i--) {                System.out.println("Thread: "+threadName +" "+ i);                // Let the thread sleep for a while.                Thread.sleep(50); //sleep your content for xx miliseconds            }        } catch (InterruptedException e) {            System.out.println("Thread " +  threadName + " interrupted.");        }        System.out.println("Thread " +  threadName + " exiting.");        //finish your work here     }    public void start () {        System.out.println("Starting " +  threadName );        if (thread == null) {            thread = new Thread (this);            thread.start (); //This will call your run methods of Runnable        }    }}//test your thread from herepublic class TestThread {    public static void main(String args[]) {        RunnableDemo R1 = new RunnableDemo( "Thread-1");        R1.start();        RunnableDemo R2 = new RunnableDemo( "Thread-2");        R2.start();    }   }