Explain System.out.println

Lets take a example of below code

public class System1 {
    static String out1="Sunil";

In above code  System1 is a class , then how you find out the length of out1 like System1.out1.length() 

here length() is defined in String class, In the same way System.out.prrintln() works

System: is a Class defined in the java.lang package
Out: is a static variable defined in System class, of type PrintStream like public static final PrintStream out;
println(): is a method defined in the PrintStream class