Variable length (Dynamic) Arrays in Java

Yes: use ArrayList.

In Java, "normal" arrays are fixed-size. You have to give them a size and can't expand them or contract them. To change the size, you have to make a new array and copy the data you want - which is inefficient and a pain for you.

Fortunately, there are all kinds of built-in classes that implement common data structures, and other useful tools too. You'll want to check the Java 6 API for a full list of them.

One caveat: ArrayList can only hold objects (e.g. Integers), not primitives (e.g. ints). In MOST cases, autoboxing/autounboxing will take care of this for you silently, but you could get some weird behavior depending on what you're doing.

Arrays in Java are of fixed size. What you'd need is an ArrayList, one of a number of extremely valuable Collections available in Java.

Instead of

Integer[] ints = new Integer[x]

you use

List<Integer> ints = new ArrayList<Integer>();

Then to change the list you use ints.add(y) and ints.remove(z) amongst many other handy methods you can find in the appropriate Javadocs.

I strongly recommend studying the Collections classes available in Java as they are very powerful and give you a lot of builtin functionality that Java-newbies tend to try to rewrite themselves unnecessarily.