Frequent question: What is the right way of implementing the Singleton pattern in Java?

What is an efficient way to implement a singleton pattern in Java?

1. Eager initialization: In eager initialization, the instance of Singleton Class is created at the time of class loading, this is the easiest method to create a Singleton class. By making the constructor as private you are not allowing other class to create a new instance of the class you want to create the Singleton.

What are the ways to create Singleton class in Java?

Singleton Class in Java

  1. Make constructor as private.
  2. Write a static method that has return type object of this singleton class. Here, the concept of Lazy initialization is used to write this static method.

Can constructor be private?

Yes. Class can have private constructor. Even abstract class can have private constructor. By making constructor private, we prevent the class from being instantiated as well as subclassing of that class.

What is singleton function?

A singleton is a function or class which can have only one instance. It’s a design pattern popularised by the “Gang of Four” in their influential Design Patterns.

What is the purpose of the Singleton pattern?

The Singleton’s purpose is to control object creation, limiting the number to one but allowing the flexibility to create more objects if the situation changes. Since there is only one Singleton instance, any instance fields of a Singleton will occur only once per class, just like static fields.

IT IS INTERESTING:  What are the slow selectors in jQuery?

How do I make singleton thread safe?

Thread Safe Singleton: A thread safe singleton in created so that singleton property is maintained even in multithreaded environment. To make a singleton class thread-safe, getInstance() method is made synchronized so that multiple threads can’t access it simultaneously.

Why singleton is not thread safe?

Singleton is mostly considered an anti-Pattern, because it brings inherent complexity to the system in terms of testing. Only DI frameworks (Spring, Dagger, etc) should be allowed to create Singletons for you rather than you writing the singletons.

What is double checked locking in singleton?

In double-checked locking, code checks for an existing instance of Singleton class twice with and without locking to make sure that only one instance of singleton gets created.

Categories PHP