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Object usage

natt walters
Greenhorn

Joined: Mar 04, 2011
Posts: 17

class Test{
int a;
Test(int i){
a=i;
}
Test incrByTen(){
Test temp=new Test(a+10);
return temp;
}
}
class RetOb{
public static void main(String args[]){
Test ob1=new Test(2);
Test ob2;

ob2=ob1.incrByTen();
System.out.println("ob1.a: "+ob1.a);
System.out.println("ob2.a: "+ob2.a);

ob2=ob2.incrByTen();
System.out.println("ob2.a after second increase: "+ob2.a);
}
}

Output

ob1.a: 2
ob2.a: 12
ob2.a after second increase: 22


If objects have to be allocated first using 'new' before any attempt to use them in the program. Then how do these lines of code work

ob2=ob1.inceByTen();

ob2=ob2.inceByTen();

as ob2 hasn't been allocated at all.

Can anybody please explain this
Vijitha Kumara
Bartender

Joined: Mar 24, 2008
Posts: 3816

If objects have to be allocated first using 'new' before any attempt to use them in the program. Then how do these lines of code work
ob2=ob1.inceByTen();
ob2=ob2.inceByTen();
as ob2 hasn't been allocated at all.

Your incrByTen() method creates an instance of the Test class and returns it so it's assigned to the reference "ob2". Hence you can use any methods from the object referred by "ob2:

And please UseCodeTags when posting code. Unformatted code makes it hard to read the post.


SCJP 5 | SCWCD 5
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natt walters
Greenhorn

Joined: Mar 04, 2011
Posts: 17

Thank you very much.
Sorry for the inconvenience. Sorry to ask but how do I do usecodetags while posting a query. I'm using my iPhone at the moment and don't have access to a PC for now. I do apologise if I should have known it by now.
Vijitha Kumara
Bartender

Joined: Mar 24, 2008
Posts: 3816

No worries . I haven't use the mobile site for posting but I'm sure you can wrap your code around [code][/code] tags for Java code.
natt walters
Greenhorn

Joined: Mar 04, 2011
Posts: 17



Thank you very much
 
Don't get me started about those stupid light bulbs.
 
subject: Object usage
 
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