Resize an Array while keeping current elements in Java?

You can’t resize an array in Java. You’d need to either:

Create a new array of the desired size, and copy the contents from the original array to the new array, using java.lang.System.arraycopy(…);
Use the java.util.ArrayList class, which does this for you when you need to make the array bigger. It nicely encapsulates what you describe in your question.
Use java.util.Arrays.copyOf(…) methods which returns a bigger array, with the contents of the original array.

Not nice, but works:
int[] a = {1, 2, 3};
// make a one bigger
a = Arrays.copyOf(a, a.length + 1);
for (int i : a)
System.out.println(i);

as stated before, go with ArrayList