How to increase the size of an array in Java?

Question

I want to store as many elements as desired by the user in an array. But how do I do it.

If I were to create an array, I must do so with a fixed size. Every time a new element is added to the array and the array becomes full, I want to update its size by '1'.

I tired various types of code, but it did not work out.

It would be of great help if someone could give me a solution regarding it - in code if possible.

Answer 1

Instead of using an array, use an implementation of java.util.List such as ArrayList. An ArrayList has an array backend which holds values in a list, but the array size is automatically handles by the list.

ArrayList<String> list = new ArrayList<String>();
list.add("some string");

You can also convert the list into an array using list.toArray(new String[list.size()]) and so forth for other element types.

Answer 2

On a low level you can do it this way:

long[] source = new long[1];
long[] copy = new long[source.length + 1];
System.arraycopy(source, 0, copy, 0, source.length);
source = copy;

Arrays.copyOf() is doing same thing.