java - Private Interfaces -
how can use methods of private interface in our code?
abstract classes cannot instantiated. so, if need use methods of abstract class, can inherit them , use methods.
but, when talk interfaces, need implement them use methods.
the private
keyword means "anyone in same class":
public class foo { private interface x {...} private class x1 implements x {...} }
this means classes declared inside of foo
can use interface foo.x
.
a common use case command pattern foo
accepts, say, strings , converts them internal command objects implement same interface.
if add second class bar
file foo.java
, can't see foo.x
.
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