How do you write a factory class in Java?

How do you write a factory class in Java?

Design Pattern – Factory Pattern

  1. Implementation.
  2. Create an interface.
  3. Create concrete classes implementing the same interface.
  4. Create a Factory to generate object of concrete class based on given information.
  5. Use the Factory to get object of concrete class by passing an information such as type.
  6. Verify the output.

What is a factory class in Java?

The factory design pattern says that define an interface ( A java interface or an abstract class) and let the subclasses decide which object to instantiate. The factory method in the interface lets a class defer the instantiation to one or more concrete subclasses.

What is factory pattern in Java with example?

The Factory Design Pattern or Factory Method Design Pattern is one of the most used design patterns in Java. According to GoF, this pattern “defines an interface for creating an object, but let subclasses decide which class to instantiate. The Factory method lets a class defer instantiation to subclasses”.

What is the factory method patterns explain with examples?

Example. The Factory Method defines an interface for creating objects, but lets subclasses decide which classes to instantiate. Injection molding presses demonstrate this pattern. Manufacturers of plastic toys process plastic molding powder, and inject the plastic into molds of the desired shapes.

What is Polymorphism in Java?

Polymorphism in Java is the ability of an object to take many forms. To simply put, polymorphism in java allows us to perform the same action in many different ways. In the technical world, polymorphism in java allows one to do multiple implementations by defining one interface.

What problem does factory pattern solve?

In class-based programming, the factory method pattern is a creational pattern that uses factory methods to deal with the problem of creating objects without having to specify the exact class of the object that will be created.

Where is the factory method used?

Factory Method lets a class defer instantiation to subclasses….It is good idea to use factory methods inside object when:

  1. Object’s class doesn’t know what exact sub-classes it have to create.
  2. Object’s class is designed so that objects it creates were specified by sub-classes.

What is a factory in coding?

In object-oriented programming (OOP), a factory is an object for creating other objects – formally a factory is a function or method that returns objects of a varying prototype or class from some method call, which is assumed to be “new”.

Is overriding possible in Java?

If subclass (child class) has the same method as declared in the parent class, it is known as method overriding in Java. In other words, If a subclass provides the specific implementation of the method that has been declared by one of its parent class, it is known as method overriding.

What is advantage of polymorphism in Java?

Advantages of Polymorphism It helps the programmer to reuse the codes, i.e., classes once written, tested and implemented can be reused as required. Saves a lot of time. Single variable can be used to store multiple data types. Easy to debug the codes.

What is factory method in Java?

Factory Method in Java. Factory method is a creational design pattern which solves the problem of creating product objects without specifying their concrete classes. Factory Method defines a method, which should be used for creating objects instead of direct constructor call (new operator).

What exactly is a class factory?

In class-based programming, a factory is an abstraction of a constructor of a class, while in prototype-based programming a factory is an abstraction of a prototype object. A constructor is concrete in that it creates objects as instances of a single class, and by a specified process (class instantiation), while a factory can create objects by instantiating various classes, or by using other allocation schemes such as an object pool.

What is factory design pattern in Java?

Factory design pattern in Java one of the core design pattern which is used heavily not only in JDK but also in various Open Source framework such as Spring, Struts and Apache along with decorator design pattern in Java. Factory Design pattern is based on Encapsulation object oriented concept.

What is a factory class?

Factory classes provide an interface for creating families of related objects. Factory classes are useful when the decision of which class to use must be done at run time and cannot be hard coded during development. Factory classes encapsulate the logic needed to decide which subclass to instantiate…

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