I created two java files: Pizza.Java and PizzaOrder.Java.
Pizza.Java
PizzaOrder.Java
I tried compiling my code using javac in the command prompt like this:
You don't have permission to write in the directory. You shouldn't put your source code in the bin directory of the JDK.
Instead, add that bin directory to your PATH and create a work directory in your user home folder.
PATH
See How to set the path in windows 7.