Shows what happens when a local variable in a method has the same name as an instance variable in your class and provides 2 ways to fix this problem (instance variable masking).

This video demonstrates a seemingly meaningless runtime error, which occurs when the name of the class is not the same as the name of the file.

The compiler generates a “non-static method X cannot be referenced from a static context” message. Shows what happens when a non-static method is called form the static main method.