CODEWITHSUNDEEP
java
employee-0
employee-0

Reputation: 1041

What does "this" point to?

Not a duplicate, This is a semantics question?

A professor at Columbia said it, the keyword this, points to the current class ( See Page 21 ). I'm 99% sure this is not correct.

I would like to say it passes to a class instance or an object. Is there a preferred way to say what this points to concisely.

Thanks, I just want my notes to be accurate.

Upvotes: 2

Views: 185

Answers (5)

Rahul Tripathi
Rahul Tripathi

Reputation: 172448

From the Oracle docs:

The keyword this may be used only in the body of an instance method, instance initializer, or constructor, or in the initializer of an instance variable of a class. If it appears anywhere else, a compile-time error occurs.

...

When used as a primary expression, the keyword this denotes a value that is a reference to the object for which the instance method was invoked (§15.12), or to the object being constructed.

From the wiki:

this

Used to represent an instance of the class in which it appears. this can be used to access class members and as a reference to the current instance. The this keyword is also used to forward a call from one constructor in a class to another constructor in the same class.

Upvotes: 7

MeBNoah
MeBNoah

Reputation: 175

this definitely refers to the current instance

Upvotes: 0

Umer Farooq
Umer Farooq

Reputation: 7486

this is a keyword used by the OO programming languages to refer to the instance of current class. It implicitly fetches the the reference or the address of the object or instance of the current class.

this in JAVA

Hope this helps

Upvotes: 0

Deepak Ingole
Deepak Ingole

Reputation: 15742

What does "this" point to?

this refers to the current object.

E.g

public class MyThisTest {
  private int a;

  public MyThisTest() {
    this(42); // calls the other constructor
  }

  public MyThisTest(int a) {
    this.a = a; // assigns the value of the parameter a to the field of the same name
  }

  public void frobnicate() {
    int a = 1;

    System.out.println(a); // refers to the local variable a
    System.out.println(this.a); // refers to the field a
    System.out.println(this); // refers to this entire object
  }

  public String toString() {
    return "MyThisTest a=" + a; // refers to the field a
  }
}

Self Explanatory Output: 

1
42
MyThisTest a=42

Upvotes: 1

asantaballa
asantaballa

Reputation: 4048

You can think of it as the "current class". But I like to think of it as a reference to the object instance in which the "this" is used.

So if you have class A and you create two instances, A1 and A2, when you refer to "this" in a method call executing in A2, "this" refers to the instance A2, not the class A.

Clear as mud?

Upvotes: 0

Related Questions