Since the introduction of generics in Java 5, it is recommenced to use generic types such as List<String>
instead of raw ones such as just List
. Assigning a raw type into a generic one is not type safe, and will generate a warning. The old EMPTY_...
fields of the Collections
class return raw types, whereas the newer empty...()
methods return generic ones.
emptyIterator()
and emptyListIterator()
methods for which there is no field equivalent if they are used to call the methods.
List<String> collection1 = Collections.EMPTY_LIST; Map<String, String> collection2 = Collections.EMPTY_MAP; Set<String> collection3 = Collections.EMPTY_SET;
List<String> collection1 = Collections.emptyList(); Map<String, String> collection2 = Collections.emptyMap(); Set<String> collection3 = Collections.emptySet();