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Spiderman • Jan 4, 2007

Plz replies me

in java language we use System.out.println. then what is System , out and println in that
akravikanth • Jan 4, 2007
Its simple,

System is a class declared as final which cannot be instantiated. It contains various classes and methods.

The three important facilities provided by the System class are Standard Input, Standard Output and error output streams.

These are normally called as streams, you can make use of the above said facilities using the following

out ----> The standard output stream
in ----> The standard input stream
err ----> The standard error output stream.

Normally after creating objects, you will access the functions aka methods
using dot(.) operator. for example, if a is an object and display() is a method, then u can access by using a.display();

Similarly, if u want to print, you will make use of the println() method using the dot operator as System.out.println(), where System is the class, out is the outputstream and println is the method.
A SudhaKar
A SudhaKar • Jan 4, 2007
System - Has multiple installed function

Out - Output stream to be printed

In - Input stream if necessary

Print ln - to print that partcular line

not satisfied with answers
can anyone please throw more light?
not satisfied with answers
can anyone please throw more light?

System is a built-in class present in java.lang package.
This class has a final modifier, which means that, it cannot be inherited by other classes.
It contains pre-defined methods and fields, which provides facilities like standard input, output, etc.

out is a static final field (ie, variable)in System class which is of the type PrintStream (a built-in class, contains methods to print the different data values).
static fields and methods must be accessed by using the class name, so ( System.out ).

out here denotes the reference variable of the type PrintStream class.
"out" is an instance of java.lang.system class

println() is a public method in PrintStream class to print the data values.
Hence to access a method in PrintStream class, we use out.println() (as non static methods and fields can only be accessed by using the refrence varialble)
print() is a method of

Shortcut for System.out.println()

you can create a PrintStream variable, assign System.out to it, and reference that object from the new variable instead.


public class TestPrint
     private static PrintStream out = System.out;

     public static void main(String args[])
    out.println(Hello, World!);
    out.println(Testing, one, two, three);

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