I fixed that error, and it really got pissed off, lol.

Timing.java:18: squared(int) in Timing cannot be applied to ()
squared();
^
If you want to learn to program in Java you are going to have to put some effort into learning to debug your own code. The compiler messages tell you what is wrong and where it is wrong. You just need to learn to decipher them and look at your code.

For example:
The message above tells you that line 18 of the Timing class has an error and it even shows you where on line 18 the error occurs (the '^' points to the position on the line above it, which is line 18 from your code). The message tells you you have a method with the same name as the one you are calling but it cannot be called in the way you are trying to call it. A quick look at the actual method and your call on line 18 shows they have a different number of parameters.