Question

In System.out.println,’out’ is a member variable of System class and it’s also an instance of PrintStream class.So can anyone please tell me whether out can be a member of System class which is an object of PrintStream class or not?And please highlight me about System.out.println.

Answer 1

It’s just a public static final variable. Any time you write:

System.out.println("Foo");

you’re fetching the value of that variable (which is a PrintStream reference) and calling println() on it. If it helps, think of it as:

PrintStream tmp = System.out;
tmp.println("Foo");

System.out is not an instance of PrintStream itself – it’s a variable. The value of the variable isn’t a PrintStream object, either – it’s a reference to an object which is either a PrintStream or a subclass instance.