Null pointer exception?

I know what the exception itself means, but I'm confused at how I'm triggering it in this situation;

Code:

---

Star str3 = null;
for (int i=0; i<20; ++i) {
        str3 = new Star();
        str3.x=(Math.random()*700-320);
        str3.y=(Math.random()*700-240);
        if (str3!=null) {
                Driver.starary.add(i,str3);
        }
}

---

I used code that was almost the EXACT same (just with more variables being set) and it works fine, so I'm confused at how this doesn't.
str3 is not used anywhere else, and x and y are doubles.

Can anyone see whats wrong?

The stack trace in the console is the place to begin. It often has the line number where the exception was thrown. If you can't figure it out from this then insert one or more println statements to check the value of variables to pinpoint the problem. Chase it down.

Oh, sorry. The line where Eclipse said the exception was called was
Driver.starary.add(i,str3);

Then I would test both Driver and Driver.starary to see if they are null:

Code:

---

Star str3 = null;
for (int i=0; i<20; ++i) {
    str3 = new Star();
    str3.x=(Math.random()*700-320);
    str3.y=(Math.random()*700-240);
    if (str3!=null) {
        System.out.println("Driver: " + Driver);
        System.out.println("Driver.starary: " + Driver.starary);
        Driver.starary.add(i,str3);
    }
}

---

Driver is definitely not null, but I may have forgotten to create a new ArrayList for starary...

*checks*

Shoot! That was it.. Thanks for the help, hardwired!