ArrayList is an implementation of Java.Util.IList, backed by an array. All optional operations including adding, removing, and replacing elements are supported.

All elements are permitted, including null.

This class is a good choice as your default List implementation. Java.Util.Vector synchronizes all operations, but not necessarily in a way that's meaningful to your application: synchronizing each call to get, for example, is not equivalent to synchronizing the list and iterating over it (which is probably what you intended). Java.Util.Concurrent.CopyOnWriteArrayList is intended for the special case of very high concurrency, frequent traversals, and very rare mutations.

[Android Documentation]