How do I pass different value to each thread in ExecutorService?

Lets say I have an array num_array = [0,1,2,3,4...30]

and I have a multi-threading function like this

static void multiThreadFunct (int[] num_array) {
    ExecutorService executor = Executors.newFixedThreadPool(25);
    try {
        Runnable r = new functToBeMultithreadded(arg1, arg2);
        executor.execute(r);
    } catch (Exception e) {
        System.out.println("err");
    }
    executor.shutdown();
}    

I wanted to know how I can pass num_array[0] to thread 1 and num_array[1] to thread 2 … num_array[24] to thread 25

Answer

Just loop over the array and pass each runnable the element:

ExecutorService executor = Executors.newFixedThreadPool(25);
for (int num : num_array) {
    try {
        Runnable r = new FunctToBeMultithreadded(num);
        executor.execute(r);
    } catch (Exception e) {
        ...
    }
}
executor.shutdown();

Note that you should not assume the order of elements will correspond to the order of threads created in the pool. That’s implementation dependent.