Java-Fail poorness to Professional

An unconventional beginning
Generally we write a HelloWorld program in java first going by the convention and obsolete ways. Let us start with a simple addition program. Even if this is your first program, believe me, you will feel much more than a newbie.
DESIGN:
import java.lang.*;
class add {
public static void main(String[] args)  {
int num1=12,num2=17;
System.out.println("Sum of "+num1+" and "+num2+" [...]