Wildcard (Java): Difference between revisions

Revision as of 19:15, 6 March 2016

Revision as of 19:22, 6 March 2016

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However, <code>new List<Generic<?>>()</code> is allowed, because the wildcard is not a parameter to the instantiated type <code>List</code>. The same holds for <code>new List<List<?>>()</code>.

An array object that is an array of a parameterized type maycan beonly created onlyparameterized by an unconstrained (i.e. with an unbound wildcard type parameter) type as the component type: <code>'''new''' Generic<?>[20]</code> is correct, while <code>'''new''' Generic<SomeType>[20]</code> is not.

For both cases, using no parameters is another option. This will generate a warning since it is less type-safe (see [[Raw type]]).

== Example: Lists ==