Updated constructor so that rather than using a null object, an object of type Object is instantiated to avoid null pointer exceptions. Null was used in the first place because all the ALU is never instantiated and relies on static fields and methods.
Updated to reflect changes to update events triggered by ALU (null replaced with Object to avoid exceptions).
Added an additional wait() in arithmetic execution blocks. Also added instruction to clear ALU fields once arithmetic operation is complete.
Added clearFields() method to reset GUI fields after arithmetic operation is complete.
ALU display now working.
Added handling for resetting ALU fields.