Java exercise tracker project

My project is an exercise tracker where effort scores will be calculated for each of the classes. I'm struggling to finish it and link each of the classes together as a hierarchy.

I need to write Activity, Run and Swim classes so they match the UML diagram and
javadoc. For phase3 I will add the InvalidActivityException class.

I have already written code for the activity class (abstract) but it's partially done.

The classes I write should then work properly with the 3 test programs
CW2Phase1, CW2Phase2 and CW2Phase3 that I have written and test data. The phase codes will not
need to be modified but rather implemented.