If a variable is a "box" that can be used to store one piece of data, than an array is a series of boxes, numbered 0 to (n-1), where n is the number of elements in a dimension. An array has one or more of these dimensions. To store a list of ten names, a one dimensional array of 10 Strings would be used. To store the status of a game of chess, an 8x8 array would be used, possibly of a custom class.
To find the number of elements in an array, use the length field.
int[] dave = new int[15];
System.out.println("The array dave can hold " + dave.length + "items of data");
If you want to copy an array, use the clone method
int ia1[] = { 1, 2 };
int ia2[] = (int[])ia1.clone();
--- won't work
String[] selectorTypes = new String["FixedValueControl", "RandomValueControl"];