Can singleton class be inherited in Java?

Unlike static classes, Singleton classes can be inherited, can have base class, can be serialized and can implement interfaces. You can implement Dispose method in your Singleton class.

Why can singleton class be inherited?

It depends on implementation. Singletons usually have private constructor and possibly marked sealed , if it is so then you can’t. If it is at least protected you can. If you just inherit from singleton class, result will not be singleton so you should follow the pattern and make it also singleton.

Can we extend singleton class in Java?

All you need to extend a singleton class is a constructor with protected or package-default in the singleton class. If there are only private constructors you simply won’t be able to extend it. If there are public constructors then it’s not a singleton class.

Can we serialize singleton class in Java?

You could do the same thing yourself, by adding custom serialization / deserialization code to your singleton classes. That code would need to either not record the singleton’s state at all, or throw it away when the singleton is deserialized.

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Can we subclass a singleton class?

@Tim In a typical singleton design, you would make the constructor private so that classes using the singleton can’t create more than one instance. However, this means that you can’t subclass it, since you can’t access the constructor from the subclass.

Can singleton class be inherited Swift?

A programmer cannot inherit the pure-singleton class. When you try to inherit any class in swift, you must call the constructor of the superclass. Calling the constructor of the superclass is not possible in pure-singleton class because all constructors of the pure-singleton class are always marked as private.

Can singleton class be inherited CPP?

Singleton in C++

Inheritance can be supported, but static functions may not be overridden. The base class must be declared a friend of the derived class (in order to access the protected constructor).

What is the best way to create Singleton class in Java?

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.

Is Singleton class thread safe?

A singleton class itself is not thread safe. Multiple threads can access the singleton same time and create multiple objects, violating the singleton concept.

Can Singleton class have methods?

7 Answers. In case of singleton classes there is no use of static methods as there is only one instance available of the class and every buddy is having the same copy of it.

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Can singleton class implements serializable?

Serialization:- Serialization can also cause breakage of singleton property of singleton classes. Serialization is used to convert an object of byte stream and save in a file or send over a network. Suppose you serialize an object of a singleton class.

Can we create clone of singleton object?

When writing a class using the Singleton pattern, only one instance of that class can exist at a time. As a result, the class must not be allowed to make a clone.

Can singleton class be cloned?

clone() is protected method and as every class in java by default extends Object class, object of any class including our Singleton class can call clone() method. If somebody will call instance. … So, if we are not implementing Cloneable interface in our Singleton class, then we do not require to prevent cloning.

Why constructor is private in singleton?

A singleton class is one which limits the number of objects creation to one. Using private constructor we can ensure that no more than one object can be created at a time. By providing a private constructor you prevent class instances from being created in any place other than this very class.

Why can’t a singleton be subclassed?

Singleton classes cannot be sub classed. Subclass instances contain a whole copy of the superclass instance. So if you can subclass a singleton, that means there would be two instances of the superclass. That, by definition, is not singleton.