LinkedHashSet is a variant on HashSet. Its entries are kept in a
doubly-linked list. The iteration order is the order in which entries were
inserted.
Null elements are allowed, and all the optional Set operations are supported.
Like HashSet, LinkedHashSet is not thread safe, so access by multiple threads
must be synchronized by an external mechanism such as
Collections.synchronizedSet.
Null elements are allowed, and all the optional Set operations are supported.
Like HashSet, LinkedHashSet is not thread safe, so access by multiple threads must be synchronized by an external mechanism such as Collections.synchronizedSet.