This simply cannot be here:
public static int indexOfLetter(char theLetter)
int index = Character.toLowerCase (theLetter)-'a';
That must be moved into your class.
Beyond this, you'll have a couple of other errors as well. One will be a compilation error, and the other will be a runtime error which is simply the placement of a closing brace. Since this is a homework assignment you should attempt to resolve these first, and come back if you have problems.
Another thing to note is that in Java, an int will always default to 0. So the loop to populate with 0 is actually optional. This differs from an Integer which defaults to null (like Object).
Also, in the future please wrap all code in [code][/code] or [php][/php] tags to preserve the formatting.