VolatileBooleanExample.java

package com.tvd12.example.concurrent.sync;

public class VolatileBooleanExample {

    private volatile boolean active;
    private static int number;

    public void prepare() throws InterruptedException {
        new Thread(() -> {
            System.out.println("application preparing ...");
            number ++;
            sleep(3);
            active = true;
        })
            .start();
    }

    public void start() throws Exception {
        new Thread(() -> {
            while(!active);
            System.out.println("application started, number = " + number);
        })
            .start();
    }

    private static void sleep(int second) {
        try {
            Thread.sleep(second * 1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws Exception {
        VolatileBooleanExample example = new VolatileBooleanExample();
        example.prepare();
        example.start();
        sleep(10);
    }
}