NetBeans - Create Java Class Library

NetBeans - Create Java Class Library
Lecture By: Mr. Malhar Lathkar, Tutorials Point India Private Limited.

[daysofmylife]

class add
{
public static void main ( String ar[ ] )
{
int x = 10 ;
int y=20 ;
int z=x+y;
System.out.println ( "The sum is" +z );
}
}
Can anyone tell me what is wrong in this because I'm getting an error.