Because the problem comes from the AP CS A test, the expectation is that only the functions you're told to write have to be implemented. Having said that, for testing on a computer, You will sometimes need additional functions/code. 

Here's the expected additions you'll need (beyond the functions described):

1. Constructor that takes in an ArrayList of Strings and sets wordList to it.

Pay close attention to what is being asked:

• The 2nd function asks you to grab the end portion of the matched String - if the target is "cat" and it's checking to see if it matches the start of "catch", then the "ch" is what is saved into the list.