Difference between System.err and System.out

Question

Hi Everyone !!!
I could see that System.err is printing an output on the screen as like the System.out.
I can't understand what is System.err.
Can anyone explain me the difference between System.out and System.err

Answer 1

System.out.println -> Sends the output to a standard output stream. Generally monitor.
System.err.println -> Sends the output to a standard error stream. Generally monitor.
To find the difference execute the following program and see the output. You will see how those streams can be handled differently.
public class test
public static void main(String args[])
System.out.println("Standard output Stream message");
System.err.println("Standard error stream message");
Compile the class.
Run the class
First Execution -
java test
Standard output Stream message
Standard error stream message
Second Execution -
java test >op.txt
Standard error stream message
In second execution we diverted only the std output stream and std err stream remained unchanged. i.e., by this way, we can handle error stream separately.
Another typical use of this stream is to produce log or debug messages at runtime and are diverted them to a file where they are archived for later use.<img class="emoticon" src="images/emoticons/shocked.gif" border="0" alt="" width="16" height="16" />