Demonstrating an ArrayList<String>
Figure 7.24 demonstrates some common ArrayList
capabilities. Line 10 creates a new empty ArrayList
of String
s with a default initial capacity of 10 elements. The capacity indicates how many items the ArrayList
can hold without growing. ArrayList
is implemented using a conventional array behind the scenes. When the ArrayList
grows, it must create a larger internal array and copy each element to the new array. This is a time-consuming operation. It would be inefficient for the ArrayList
to grow each time an element is added. Instead, it grows only when an element is added and the number of elements is equal to the capacity—i.e., there’s no space for the new element.
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