little help

<syntaxhighlight>Compiling... Arg.java:32: package Point2D does not exist public Point2D.Double guessPosition(long when) {

             ^

Arg.java:36: cannot find symbol symbol : variable time location: class argeaer.Arg

   double diff = when - time;
                        ^

Arg.java:40: cannot find symbol symbol : variable changehead location: class argeaer.Arg

   if (Math.abs(changehead) > 0.00001) {
                ^

Arg.java:41: cannot find symbol symbol : variable speed location: class argeaer.Arg

       double radius = speed/changehead;
                       ^

Arg.java:41: cannot find symbol symbol : variable changehead location: class argeaer.Arg

       double radius = speed/changehead;
                             ^

Arg.java:42: cannot find symbol symbol : variable changehead location: class argeaer.Arg

       double tothead = diff * changehead;
                               ^

Arg.java:43: cannot find symbol symbol : variable y location: class argeaer.Arg

       newY = y + (Math.sin(heading + tothead) * radius) - 
              ^

Arg.java:43: cannot find symbol symbol : variable heading location: class argeaer.Arg

       newY = y + (Math.sin(heading + tothead) * radius) - 
                            ^

Arg.java:43: sin(double) in java.lang.Math cannot be applied to (<nulltype>)

       newY = y + (Math.sin(heading + tothead) * radius) - 
                       ^

Arg.java:44: cannot find symbol symbol : variable heading location: class argeaer.Arg

                     (Math.sin(heading) * radius);
                               ^

Arg.java:43: operator - cannot be applied to <nulltype>,double

       newY = y + (Math.sin(heading + tothead) * radius) - 
                                                         ^

Arg.java:45: cannot find symbol symbol : variable x location: class argeaer.Arg

       newX = x + (Math.cos(heading) * radius) - 
              ^

Arg.java:45: cannot find symbol symbol : variable heading location: class argeaer.Arg

       newX = x + (Math.cos(heading) * radius) - 
                            ^

Arg.java:46: cannot find symbol symbol : variable heading location: class argeaer.Arg

                     (Math.cos(heading + tothead) * radius);
                               ^

Arg.java:46: cos(double) in java.lang.Math cannot be applied to (<nulltype>)

                     (Math.cos(heading + tothead) * radius);
                          ^

Arg.java:45: operator - cannot be applied to <nulltype>,double

       newX = x + (Math.cos(heading) * radius) - 
                                               ^

Arg.java:51: cannot find symbol symbol : variable y location: class argeaer.Arg

       newY = y + Math.cos(heading) * speed * diff;
              ^

Arg.java:51: cannot find symbol symbol : variable heading location: class argeaer.Arg

       newY = y + Math.cos(heading) * speed * diff;
                           ^

Arg.java:51: cannot find symbol symbol : variable speed location: class argeaer.Arg

       newY = y + Math.cos(heading) * speed * diff;
                                      ^

Arg.java:51: incompatible types found : <nulltype> required: double

       newY = y + Math.cos(heading) * speed * diff;
                                            ^

Arg.java:52: cannot find symbol symbol : variable x location: class argeaer.Arg

       newX = x + Math.sin(heading) * speed * diff;
              ^

Arg.java:52: cannot find symbol symbol : variable heading location: class argeaer.Arg

       newX = x + Math.sin(heading) * speed * diff;
                           ^

Arg.java:52: cannot find symbol symbol : variable speed location: class argeaer.Arg

       newX = x + Math.sin(heading) * speed * diff;
                                      ^

Arg.java:52: incompatible types found : <nulltype> required: double

       newX = x + Math.sin(heading) * speed * diff;
                                            ^

Arg.java:54: package Point2D does not exist

   return new Point2D.Double(newX, newY);
                     ^

25 errors Compile Failed (1)

This errors does not match to code. But i may guess, that you need to read about java "package" and "import" keywords and in common some basic book about java

Java Tutorial is a good place to learn Java.

And after getting used to the language, I recommend using some advanced IDE like Eclipse. All the errors above would be automatically corrected by pressing Ctrl-Shift-O.