Can you extend singleton

It is impossible to say without knowing more about the specific singleton implementation you are trying to extend, which clearly we don't have. Rob Spoor. 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. Note that to use a package-default constructor your class needs to be in the same package as the singleton class; visibility of constructors is no different than the visibility of methods or fields.

Pat Farrell. Of course, you should never actually do this. Singletons are evil and should be avoided. Email Required, but never shown. The Overflow Blog. Podcast Explaining the semiconductor shortage, and how it might end.

Does ES6 make JavaScript frameworks obsolete? Featured on Meta. Now live: A fully responsive profile. Linked Related Hot Network Questions. Question feed. Stack Overflow works best with JavaScript enabled. We can use this private constructor in the Singleton Design Pattern.

To call a constructor, an object must be created. What is Overloading and Overriding? Can we extend Singleton class? Can we use this and super in a method? Can we have private constructor in C? What happens if we override static method? 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. Pros: It is also thread safe. Singleton design pattern is a software design principle that is used to restrict the instantiation of a class to one object.

This is useful when exactly one object is needed to coordinate actions across the system. What is the use of design patterns? Design patterns are guidelines used by developers to solve common structural problems that they often encounter when building an application. These patterns increase code readability and reduce the amount of code changes in the source code whenever you need to fix a bug, or add a new feature.

You have a class that must only ever be instantiated once, and you need to provide a way for clients to access that class in such a way that the same, single object is returned each time. This is commonly referred to as a singleton pattern, or a singleton class. Why do we need sealed class in C? Sealed classes are used to restrict the inheritance feature of object oriented programming.

Once a class is defined as a sealed class, this class cannot be inherited. In C , the sealed modifier is used to declare a class as sealed.

If a class is derived from a sealed class, compiler throws an error.