使用递归的手机文本预测（Java）

I'm having some trouble on a Java assignment for school. We need to write a program that does T9 Word text prediction used by certain cell phones. It should take a user's input of numbers, find every possible combination of letters corresponding to those numbers, search a dictionary for each of those possible combinations, and display those which were found in the dictionary. Most of this program was already written for us by the professor, I just need to fill in the predictText method which does the combining of possibilities. It does the searching by calling another method that uses a recursive binary search, which I also had to fill in myself, although I'm quite certain my search method is working well. Here is my predictText method, where parameter "letter" is the letter being currently processed, parameter input is the user's input, and parameter "wordMatches" is the list of words that have been found in the dictionary.I'm having some trouble on a Java assignment fo