Java Inner Class (4): Static inner Class & interface inner class

Internal classes that use static adornments are called static inner classes, but we prefer to call them nested inner classes . There is one big difference between static inner and non-static inner classes, and we know that a non-static inner class implicitly holds a reference after compilation, which points to the perimeter in which it was created, but does not have a static inner class. Without this reference, it means:

1, its creation is not required to rely on the peripheral class.

2. It cannot use non-static member variables and methods of any perimeter class.

1 InterfaceContents {2     intvalue ();3 }4 5 InterfaceDestination {6 String Readlabel ();7 }8 9 classTest005sub {Ten  One     Private Static classParcelcontentsImplementsContents { A         Private inti = 11; -  -          Public intvalue () { the             returni; -         } -     } -  +     Static classParceldestinationImplementsDestination { -         PrivateString S; +  A         Privateparceldestination (String s) { at              This. S =s; -         } -  -          PublicString Readlabel () { -             returns; -         } in  -          Public Static voidf () { to         } +  -         Static intx = 10; the  *         Static classAnotherlevel { $             {Panax Notoginsengx = 111; - System.out.println (x); the             } +         } A     } the  +      Public StaticContents Contents () { -         return Newparcelcontents (); $     } $  -      Public StaticDestination Destination () { -         return NewParceldestination ("Hello world!"); the     } - }Wuyi  the  Public classTest005 { -      Public Static voidMain (string[] args) { WuContents C =test005sub.contents (); -Destination d =test005sub.destination (); About         NewTest005Sub.ParcelDestination.AnotherLevel ();//111 $System.out.println (C.value ());// One -System.out.println (D.readlabel ());//Hello world! -     } -}

There is also an interface inner class that is placed in the interface

Any classes placed in an interface are automatically public and static , so placing nested classes within the namespace of an interface does not violate the rules of the interface.

1 InterfaceTest006sub {2 3     voidhowdy ();4 5     classTestImplementsTest006sub {6          Public voidHowdy () {7System.out.println ("howdy!");8         }9     }Ten } One  A  Public InterfaceTest006 { -      Public Static voidMain (string[] args) { -         NewTest006sub.test (). Howdy ();//howdy! the     } -}

Java Inner Class (4): Static inner Class & interface inner class