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Ajay Raja
Ajay Raja

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Constructor_Keywords

This Keyword

What is this?

  • this is a Keyword in Java that refers to the current object of the class.
  • It is a fundamental concept in object-oriented programming.

When we use this?

  • When local variables and instance variables have the same name.
  • can be used within a constructor to call another constructor of the same class.
  • When you want to pass the current object to another method or constructor.

How it will be used?

  • this.variable --- access current object variable.
  • this.method() --- call a method of the same class.
  • this() → call another constructor of the same class.

Where we use?

  • In constructors ---- to call another constructor.
  • In instance methods ---- to access variables/methods of the same object.
  • When passing the current object ---- as a parameter.

Why we use?

  • To reuse constructors instead of duplicating code.
  • To remove confusion between local and instance variables.

super keyword

What is super?

  • super is a keyword that refers to the parent class object.

When we use super?

  • When you want to call the parent class constructor.
  • When a child class overrides a method but you still need the parents one.
  • When parent and child class variables have the same name.

How it will be used?

  • super.variable ---- access parent class variable.
  • super.method() ---- call parent class method.
  • super() ---- call parent class constructor (must be first statement).

Where we use?

  • inside the child class only.
  • super() can only be in constructors.
  • super.variable/method can be inside child methods.

Why we use?

  • To avoid code duplication in constructors.
  • To access hidden parent members that are overridden in child.
  • To achieve reusability of parent class features.

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