CODEWITHSUNDEEP
java
WolfSkin
WolfSkin

Reputation: 93

Where "this" is referring

Mate, I have a very simple code where I am printing "this" along with "object" of the class. As per theory "this" refers to current "object", but in my code it looks like "this" is not referring to current object. Need some guidance please

This is my output :

costructor this hash : Sandbox.Apple@1540e19d
newApple hash : Sandbox.Apple@1540e19d
this hash : Sandbox.Apple@1540e19d
costructor this hash : Sandbox.Apple@677327b6
apples hash : Sandbox.Apple@677327b6
this hash : Sandbox.Apple@1540e19d

My Question is why the last line of the output i.e. 

this hash : Sandbox.Apple@1540e19d

is referring to 1540e19dinstead of 677327b6

public class ThisKeyword {

public static void main(String[] args) {
    // TODO Auto-generated method stub

    Apple newApple = new Apple("Green Apple");
    System.out.println("newApple hash : " + newApple);

    newApple.calculateQuantity();
    newApple.testThis();
}

}

class Apple {
    String name;

public Apple(String name) {
    this.name = name;
    // TODO Auto-generated constructor stub
    System.out.println("costructor this hash : " + this);
}

public void calculateQuantity() {

    System.out.println("this hash : " + this);
}

public void testThis() {
    Apple apples = new Apple("Red Apple");
    System.out.println("apples hash : " + apples);
    System.out.println("this hash : " + this);
}

}

Upvotes: 0

Views: 151

Answers (4)

James S
James S

Reputation: 308

It's working as it should.

You're creating two Apple objects here, newApple (created in the main method) and apples (created in testThis()).

In Apple.testThis(), the line System.out.println("this hash : " + this); is referencing the Apple object you're calling it from which is the variable newApple, not apples.

Upvotes: 1

user2879327
user2879327

Reputation:

The last method call you make is newApple.testThis(); in which you call System.out.println("this hash : " + this);, since you are calling the method on newApple, then this refers to newApple, not apples.

Upvotes: 0

simpletron
simpletron

Reputation: 739

this refer to current instance of the defined class, mean it refers to the object whose method is being called.

The last line output is the product of newApple.testThis() and of course it refers to newApple with 1540e19d

Upvotes: 0

tianwei
tianwei

Reputation: 1879

Because when you call method newApple.testThis();, the context of this is the object newApple which has a reference address 1540e19d. So statement System.out.println("this hash : " + this); should print the address 1540e19d.

Meanwhile, statements:

Apple apples = new Apple("Red Apple");
System.out.println("apples hash : " + apples);

gave the new address of the new object apples ,which is 677327b6.

Upvotes: 0

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