使用默认方法进行接口

// 来自 NowJava.com - 时代Java

interface Movable {

  void setX(double x);


  void setY(double y);


  double getX();


  double getY();


  // A default method

  default void move(double deltaX, double deltaY) {

    double newX = getX() + deltaX;

    double newY = getY() + deltaY;

    setX(newX);

    setY(newY);

  }

}/**来自 时   代     Java  公  众  号 - nowjava.com**/


class Pen implements Movable {

  private double x;

  private double y;


  public Pen() {

    // By default, the pen is at (0.0, 0.0)

  }


  public Pen(double x, double y) {

    this.x = x;

    this.y = y;

  }


  public void setX(double x) {

    this.x = x;

  }


  public void setY(double y) {

    this.y = y;

  }


  public double getX() {

    return x;

  }


  public double getY() {

    return y;

  }


  public String toString() {

    return "Pen(" + x + ", " + y + ")";

  }

}


public class Main {

  public static void main(String[] args) {