ThreadLocal

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

class MyRunnable implements Runnable {

    private static final ThreadLocal<Integer> thrLoc1 = new ThreadLocal<Integer>() {
        @Override
        protected Integer initialValue() {
            return new Integer(777);
        }
    };

    // same as lambda arg: Supplier<T>, T get()
    private static final ThreadLocal<Integer> thrLoc2 = ThreadLocal.withInitial(() -> 777);

    @Override
    public void run() {
        thrLoc1.set(thrLoc1.get() + 1); // increment Integer (ThreadLocal var)
        System.out.println(thrLoc1.get());
        System.out.println(thrLoc2.get());
        thrLoc2.set(111);
        System.out.println(thrLoc2.get());
        thrLoc1.remove();
        thrLoc2.remove();   // prevents memory leak
    }
}

public class Driver {

    public static void main(String[] args) {

        // USING EXECUTOR FRAMEWORK LIKE BELOW NOT RECOMMENDED!
        // USE Thread t = new Thread(Runnable), t.start
        ExecutorService es1 = Executors.newSingleThreadExecutor();
        ExecutorService es2 = Executors.newSingleThreadExecutor();
        Runnable r = new MyRunnable();

        es1.submit(new MyRunnable());
        es2.submit(new MyRunnable());
    }
}