why is masses not found?

Hello, Im still trying to make part1 of day2 working at a way I can also test things. the tests are working but when I call on the class side the method which should reed the masses which are on the instanc side , the masses cannnot be found. So question 1 is why is masses not found. and question 2  is how can I use the changed array at the process method so I can calculate the outcome. Regards, Roelof