Why System.out

'out' is an object of InputStream class .Then why we use it with system class as we write System.out.print() to print some message

First, System.out is an OutputStream -- not an InputStream.

But to answer your question... standard out has to be provided somehow. What do you propose to use instead?

Henry

@Henry

I am not proposing aything..I just want to know how we are able to use object of one class with some other class

Anchit Jindal wrote:
I am not proposing aything..I just want to know how we are able to use object of one class with some other class

It is perfectly valid for any class to have a final static variable that refers to an instance of another class.

Henry

Same way we can use any class's variable if it's defined in such a way that gives us access.

Did that answer your question Anchit? I think your initial question reads like a challenge to Java, when really you meant it sincerely. The System class in Java contains a number of fields (like "in" and "out"), and methods (like currentTimeMillis()), which are useful to basic programming. However, looked at another way the whole System class is a sacrifice of elegance for convenience. We Java guys can be sensitive about that.

It should also be remembered that System is a very old (1.0) class, and the way things were done at the beginning of Java were not necessarily the best way to do things. It's easy to have 20/20 hindsight, but public APIs are hard to change once they're released into the wild.

John.