Table of Contents
Can we clone a singleton object in Java?
Simple answer is No you should not. Cloning itself defeats the purpose of having singleton object. So ideally your Singleton class should not implement the Cloneable interface at all.
How do you clone a singleton object?
Cloneable interface must be implemented by the class whose object clone we want to create. If we don’t implement Cloneable interface, clone() method generates CloneNotSupportedException . So, if we are not implementing Cloneable interface in our Singleton class, then we do not require to prevent cloning.
Can you clone an object in Java?
Clone() method in Java. Object cloning refers to the creation of an exact copy of an object. It creates a new instance of the class of the current object and initializes all its fields with exactly the contents of the corresponding fields of this object. In Java, there is no operator to create a copy of an object.
Can we modify singleton object Java?
From your singleton class, if the object is created then no objects are allowed to modify the someNum & someString values because of a singleton pattern.
Is Java clone a deep copy?
clone() is indeed a shallow copy. However, it’s designed to throw a CloneNotSupportedException unless your object implements Cloneable . And when you implement Cloneable , you should override clone() to make it do a deep copy, by calling clone() on all fields that are themselves cloneable.
When singleton is not singleton in Java?
A singleton (in Java land) wouldn’t work as a singleton if a given class is loaded by multiple class-loaders. Since a single class can exist (or can be loaded) in multiple classloaders, it’s quite possible to have “multiple” instances of a “supposedly” singleton class for a given JVM instance.
Can we create a clone of a singleton object True or false?
true. It is possible to get a clone of singleton object. Q 11 – If we serialize a singleton object and deserialize it then the result object will be same.
Is it possible to clone singleton object True or false?
true. It is possible to get a clone of singleton object. Throw exception within the body of clone() method to prevent cloning. Q 11 – If we serialize a singleton object and deserialize it then the result object will be same.
Which method can help you serialize singleton class?
Defining readResolve() method ensures that we don’t break singleton pattern during DeSerialization process.
Do we need to prevent cloning in singleton class in Java?
No. The java.lang.Cloneable interface must be implemented by the class whose object clone we want to create. If we don’t implement Cloneable interface, clone () method generates CloneNotSupportedException. So, if we are not implementing Cloneable interface in our Singleton class, then we do not require to prevent cloning.
What is object cloning in Java?
The object cloning is a way to create exact copy of an object. So if somebody will clone our singleton instance, it will create another copy of the Singleton instance which violates principle of Singleton Design Pattern. How does Java support Cloning?
Why there are two objects of a singleton class in Java?
As you can see, hashCode of both instances is different, hence there are 2 objects of a singleton class. Thus, the class is no more singleton. Overcome serialization issue:- To overcome this issue, we have to implement method readResolve () method.
Why can’t I call clone() on a singleton?
The clone () method by default is protected, so no class (except those in the same package) would be able to call it on that Singleton instance. Plus, if this Singleton does not implement Cloneable, then even if this method is called, it will give a runtime exception.