("Executing method2");}}// Combined class using inheritance and compositionclassCombinedClassextendsDerivedClass1{privateDerivedClass2 obj2=newDerivedClass2();// Additional method utilizing behavior from both classesvoidcombinedMethod(){commonMethod();obj2.method2();}}// Main class for testing...
out.println("Current Speed : " + speed); } public class SimpleTesting extends Run { public static void main(String[] args) { SimpleTesting run = new SimpleTesting(); run.showSpeed(); run.speed = 20; run.showSpeed(); } } } 输出: Current Speed : 0 Current Speed : 20 在Java ...
通过使用关键字extends,子类可以继承父类的除 private 属性外所有的属性。 我们通过使用 instanceof 操作符,能够确定 Mammal IS-A Animal 实例 public class Dog extends Mammal{ public static void main(String args[]){ Animal a = new Animal(); Mammal m = new Mammal(); Dog d = new Dog(); System...
1.1.5 匿名内部类 如下所示代码为定义一个匿名内部类:匿名内部类通常用在Java的事件处理上 import java.applet.*; import java.awt.event.*; public class AnonymousInnerClassDemo extends Applet{ public void init(){ addMouseListener(new MouseAdapter(){ public void mousePressed(MouseEvent me){ showStatus...
class Employee extends Person { String office; String salary; MyDate hiredDate; public Employee(String n) { super(n); } @Override public String toString() { return "Employee" + this.name; }}class MyDate { String year; String month; String day; public MyDate(String y, String m, ...
public Class SubClass extends SuperClass implements SuperInterface { { System.out.println(“init SubClass field”); } public SubClass() { System.out.println(“init SubClass Constructor”); } public void someMethod() { System.out.println(“run SubClass someMethod()”); ...
extends:继承,一个类可以继承另一个类的变量和方法,最多继承一个类。 implements:实现,一个类或者抽象类可以实现一个或者多个接口。 虽然一个类只能继承一个类,但是子类还可以被孙子类继承一次,孙子类还可以被重孙子类继承,对于最低级的类来说,它将继承上所有上级类的变量和方法,只是extends关键字后最多只能有一...
importjava.applet.Applet;importjava.awt.event.MouseAdapter;importjava.awt.event.MouseEvent;publicclassMyTestextendsApplet{publicvoidinit(){ addMouseListener(newMouseAdapter(){publicvoidmousePressed(MouseEvent me){ showStatus("Mouse Pressed!");
5.接口的扩展方法:public interface接口1 extends接口2 6.(1)通常接口的名字以able或ible结尾;(2)可以使用extends来继承接口的常量和抽象方法,扩展形成新的接口;(3)接口中的所有常量必须是public staticfinal,方法必须是public abstract,这是系统默认的,不管你在定义接口时,写不写修饰符都是一样的。
First of all, Object class is the super/base/parent class of every class including user-defined classes. So even if we don't mention it explicitly, the user-defined classes extends Object class by default. its like class A class B extends A but compiler read it as class...