What's the meaning of System.out.println in Java?

Question

Is this static println function in out class from System namespace?

 namespace System {   class out {     static println ...   } 

How can I interpret this name? And where in JRE this function is defined? In java.lang.System/java.lang.Object?

Answer 1

No. Actually out is a static member in the System class (not as in .NET), being an instance of PrintStream. And println is a normal (overloaded) method of the PrintStream class.

See http://download.oracle.com/javase/6/docs/api/java/lang/System.html#out.

Actually, if out/err/in were classes, they would be named with capital character (Out/Err/In) due to the naming convention (ignoring grammar).

Answer 2

System is a class, that has a public static field out. So it's more like

class System  {     public static PrintStream out; }  class PrintStream {     public void println ... } 

This is a slight oversimplification, as the PrintStream class is actually in the java.io package, but it's good enough to show the relationship of stuff.