Well, you are right in posting the question here, Threads will be the solution to your problem, if you want to perform multiple tasks in parallel.
You showed us some code that does the task serially, what have you tried to do to make them run at the same time? Have you tried to create a threaded implementation? Have you read
the Java Concurrency Tutorial?
If so, post some of the things you tried and let us know what problems you had, so we can help you fix them. If not, try to implement the the threaded version of your code yourself and ask specific questions when you run into problems, you will learn more that way.