StringBuffer

[Kalyani Marathe]

Hi,

I want to know why this doesn't give error:

 
final StringBuffer a = new StringBuffer("A"); 
final StringBuffer b = new StringBuffer("B"); 
a.append("add1");
a.append("add2");
System.out.println(a ); 

It prints "Aadd1add2"

Thanks.

[Tony Morris]

...because it is legal Java language syntax.
Be more specific.

[Kalyani Marathe]

Even if I declare it final it will change? Why is it possible?

Thanks.

[Jon Egan]

I'm going to guess that Kalyani meant "why am I allowed to modify an object that is declared to be final?".

What is final in this case is not the object itself, but the object reference, meaning that you can't reassign the variable "a" to reference some other StringBuffer. Declaring the reference variable to be final does not make the object to which the reference points immutable.

-- Jon

[Raghu Shree]

If you declared object as final you can't reassign another object reference to the object.But we can change the instance member values.

final StringBuffer a = new StringBuffer("A");
final StringBuffer b = new StringBuffer("B");
b=new StringBuffer("BBBB"); // It shows error message
a.append("add1");
a.append("add2");
System.out.println(a );

Here object a reference can't be changed. so it doesn't show any error messages.

[Kalyani Marathe]

Now I got the point.

Thanks.