Error: Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException

[romina]

I've started learning java and I have a problem executing this,

public class IfDemo
{
public static void main(String [] args)
{

int x = Integer.parseInt(args[0]);
double half = 0.0;
if(x!=0)
{
half = x/2.0;
System.out.println(x+"/2="+half);

}
if(x==0)
{
System.out.println("Nothing found.");
}
int y = x*5;
char grade ='F';
if(y >= 85)
{
grade='A';
}

if(y>=70 &&y<85)
grade='c';
System.out.println("y= "+y+" and grade = "+grade);
}

}

It compiles fine (I use Jcreator) but when I execute it I get this message :

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at IfDemo.main(IfDemo.java:7)

Thanks.

[Seemster]

args[0] is null. if running from the command line are you passing in a value for arg[0] which gets assigned to x. if running from within an ide, such as eclipse, open up the run menu and pass a value to the program. if you can't do that, comment out int x = Integer.parseInt(args[0]) and change it to x = 3 (or some value).