I'm not sure of the purpose here. Is the goal to memorize the arraylist and hashmap source, so that when the same question is asked, you can answer the question? I think it may be more productive to try to write it yourself -- this way, when asked again, you can reproduce it during the interview.
Regardless, if you really want to see the source. The source for the arraylist and hashmap classes should be included with your Java install (if you have the full SDK). It is part of the source file located at src.zip.
Such questions are usually followed by discussion on performance improvements and time space trade offs. You should probably follow Henry's suggestion and try to do it yourself. Only when you understand the implementation can you discuss any improvements to it.
Hint -> Think of how lists can be implemented with an array. What are the methods that a List must have ?
With hash maps there is so much to discuss. Here is a starter Hash table.