interface Collection{ void add(); void remove(); //new requirement: project need add a new method //but we can't overrided the method in each implements classes //default method is to solve this problems default void put(){ System.out.println("put the key in"); } } class List impl...
1、default Method or static method in interface 1.1 default method Java 8 之前,为一个已有的类库增加功能是非常困难的。具体的说,接口在发布之后就已经被定型,除非我们能够一次性更新所有该接口的实现,否则向接口添加方法就会破坏现有的接口实现。Default method的目标即是解决这个问题,使得接口在发布之后仍能被逐...
Implementing Inheritance Rules of Default Methods Implementing Inheritance Rules of Default Methods Overview Creating a Java Project Extending Interfaces Without Default Methods Extending Interfaces with Default Methods Summary
Notice that log(String str) is the default method in theInterface1. Now when a class will implement Interface1, it is not mandatory to provide implementation for default methods of interface. This feature will help us in extending interfaces with additional methods, all we need is to provide...
public interface MyInterface { // regular interface methods default void defaultMethod() { // default method implementation } } The reason why the Java 8 release included default methods is pretty obvious. In a typical design based on abstractions, where an interface has one or multiple implement...
override abstract method doSomeOtherWork()inSimpleInterface class SimpleInterfaceImpl implements SimpleInterface{ ^ 1 error 因为接口有这个语法限制,所以要直接改变/扩展接口内的方法变得非常困难。我们在尝试强化Java 8 Collections API,让其支持lambda表达式的时候,就面临了这样的挑战。为了克服这个困难,Java 8中引...
public interface SimpleInterface { public void doSomeWork(); //A default method in the interface created using "default" keyword //使用default关键字创在interface中直接创建一个default方法,该方法包含了具体的实现代码 default public void doSomeOtherWork(){ ...
通过default method，很多JDK里原有的接口都添加了新的可以接收FunctionalInterface参数的方法，使它们更...
// TODO Auto-generated method stub } } interface InterfaceA{ public void saySomething(); default public void sayHi(){ System.out.println("Hi"); } } 要注意,我们必须提供所有的default方法的实现。因此,default方法使我们的代码更加灵活,在接口中也可以写方法实现了。实现的方法会作为默认的方法实现。
public void callDefaultMetho InterfaceA interfaceA = this; interfaceA.defaultMethod(; } ``` 在callDefaultMethod(方法中,我们创建了一个InterfaceA类型的引用,并将其指向当前对象。然后,我们通过interfaceA.defaultMethod(调用了InterfaceA接口的默认方法。这将输出"This is the overridden method in ClassC"。