How to implement a singleton pattern?

Create a public class having a private constructor. Private constructor ensures that the object cannot be created outside of the class.

Create a private static variable of the type Class itself.

Create a public static method e.g. getInstance() that returns the reference of the static variable, if the static variable is null then create a object for the class.

package org.javatutorials.designpatterns;

//Step 1
public class SingletonPattern {

	//Step 2
	private static SingletonPattern mySingletonObj;

	private SingletonPattern() {

	}

	public static SingletonPattern getInstance() {

		if (mySingletonObj == null) {
			mySingletonObj = new SingletonPattern();

		}

		return mySingletonObj;
	}
}

Use Robinhood app to invest in stocks. It is safe and secure. Use the Referral link to claim your free stock when you sign up!.

The Robinhood app makes it easy to trade stocks, crypto and more.