java1.8-Functional Interface

Package com.wzy.t1; @FunctionalInterface//This annotation is used to declare that this interface is a functional interface Public Interfacepeople {/** * 1. A functional interface can have only one abstract method, not a single method, * because the Equals () method is implemented in Java.lang.Object, it also conforms to the functional specification * 2. If there is only one abstract method within this interface,     So even if you do not write @functionalinterface, it is also considered a functional interface * 3. There can be many default methods * 4. Using the default keyword, you can define an instance method within an interface.     * Note that this method is not an abstract method, but rather a concrete instance method with specific logic. * */     Public voideat (); //Public void Eat2 ();//there will be a second error .     Publicboolean equals (Object obj);
Interface Default Methoddefault  Public voidsleep () {System. out. println ("lie down and sleep."); }    default  Public voidrun () {System. out. println ("walking. "); }}

Package com.wzy.t1;  Public Interface Student {    publicvoid  eat ();     default void run () {        System. out. println (" small run ");}    }

Package com.wzy.t1; Public classMain implements people,student{ Public Static voidMain (string[] args) {NewMain (). run (); NewMain (). Eat (); NewMain (). Sleep (); } @Override Public voidrun () {//Multiple inheritance: When the same default method is present on two interfaces, you must redefine the interface yourself, or specify which default method to use for which interfacePeople.super.sleep ();        People.super.run ();    Student.super.run (); } @Override Public voideat () {System. out. println ("Big Stutter"); }}

java1.8-Functional Interface