How to increase an array's length

If you don't want or cannot use ArrayList, then there is a utility method:

Arrays.copyOf() 

that will allow you to specify new size, while preserving the elements.

Arrays in Java are of fixed size that is specified when they are declared. To increase the size of the array you have to create a new array with a larger size and copy all of the old values into the new array.

ex:

char[] copyFrom  = { 'a', 'b', 'c', 'd', 'e' };
char[] copyTo    = new char[7];

System.out.println(Arrays.toString(copyFrom));
System.arraycopy(copyFrom, 0, copyTo, 0, copyFrom.length);
System.out.println(Arrays.toString(copyTo));

Alternatively you could use a dynamic data structure like a List.

I would suggest you use an ArrayList as you won't have to worry about the length anymore. Once created, you can't modify an array size:

An array is a container object that holds a fixed number of values of a single type. The length of an array is established when the array is created. After creation, its length is fixed.

(Source)