When to call this() and when to call super() in java?

Question

Can any one please tell me what is the difference between super() call and this() call in java constructors?

A google-able question . super() is for calling superclass' constructor . this() is current class — Caffeinated, Feb 25 '14 at 15:57
`this` refers to constructor of (guess what...) current (this) class. `super` refers to constructor of superclass. — Pshemo, Feb 25 '14 at 15:57

score 2 · Answer 1 · answered Feb 25 '14 at 15:57

2

super() means the super class (parent) and this() means the current class.

answered Feb 25 '14 at 15:57

Henrik

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score 2 · Answer 2 · answered Feb 25 '14 at 15:58

2

this() calls another constructor for the same class. In this case the 0 argument one.

super() calls the constructor for the super class.

answered Feb 25 '14 at 15:58

Colin D

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score 2 · Answer 3 · answered Feb 25 '14 at 15:58

2

super() calls no-argument constructor from superclass and this() calls no-arg constructor from the current class.

answered Feb 25 '14 at 15:58

Jakub H

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score 1 · Accepted Answer · edited Feb 25 '14 at 16:30

super() calls the parent constructor of the class and this() calls the constructor defined within the class.

//Example of super()
class parent
{
  parent()
  {

  }
}
class child()
{
   child()
   {
      super();   //Go to parent class constructor
   }
}


//Example of this    
class test
{
    test()
    {
       this("a");  //go to test one argument constructor within the test class
    }
    test(String a)
    {

    }

}

score 1 · Answer 5 · answered Feb 25 '14 at 15:58

1

super() refers to the base/parent class. Can be used in constructor to invoke parent constructor but must be done in the declaration of the constructor.

answered Feb 25 '14 at 15:58

T McKeown

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score 1 · Answer 6 · answered Feb 25 '14 at 15:59

1

It means you are delegating part of the object construction to another constructor, being super() a constructor defined in a superclass and this() a constructor defined in the same class.

answered Feb 25 '14 at 15:59

renke

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score 0 · Answer 7 · edited May 23 '17 at 12:33

0

The super() is for calling superclass' constructor . this() refers to the current class .

Here are good SO-links.

this and super in java

Difference between "this" and"super" keywords in Java

edited May 23 '17 at 12:33

Community

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answered Feb 25 '14 at 15:58

Caffeinated

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When to call this() and when to call super() in java?

7 Answers7