Android/Java Singleton class boilerplate.

MySingleton.java

/*
 * A Singleton class, based on an article on Medium, "How to make the perfect Singleton?"
 * Link: https://medium.com/@kevalpatel2106/how-to-make-the-perfect-singleton-de6b951dfdb0
 */

package com.myapp.singleton; // Your package name

public class MySingleton {
    private static volatile MySingleton instance;

    private MySingleton() {
        if (instance != null) {
            throw new RuntimeException("Use getInstance() method to get the single instance of this class.");
        }
    }

    public static MySingleton getInstance() {
        if (instance == null) {
            synchronized (MySingleton.class) {
                if (instance == null) instance = new MySingleton();
            }
        }
        return instance;
    }
    
    ////////////////////////////////////////////////
    // Put your code here
    ////////////////////////////////////////////////

}