NOTE

Java List Implementations Compared

Choosing among ArrayList, LinkedList, CopyOnWriteArrayList, and synchronized wrappers by access pattern.

JavaCreated 01/17/2020Updated 09/15/20261 min readhistorical

This is a historical learning note and may contain outdated or incomplete understanding.

Use ArrayList as the default general-purpose list: it has compact storage, fast indexed reads, and good locality.

LinkedList is useful only for workloads that truly benefit from linked deque/list semantics. CopyOnWriteArrayList is specialized for small/read-mostly concurrent collections with rare writes. Collections.synchronizedList serializes access through a wrapper lock and still requires synchronization during iteration according to its contract.

Choose by real access/concurrency patterns rather than memorizing one complexity table.