Java中接口和抽象类有什么区别？

// 接口定义
interface Shape {
    double getArea(); // 计算面积
    double getPerimeter(); // 计算周长
}

// 抽象类实现
abstract class AbstractShape implements Shape {
    private String color; // 共有的属性

    public AbstractShape(String color) {
        this.color = color;
    }

    public String getColor() {
        return color;
    }

    // 部分实现
    @Override
    public double getPerimeter() {
        // 默认实现，子类可以重写
        return 0;  //  需要子类根据形状具体实现
    }
}

// 具体实现
class Circle extends AbstractShape implements Shape {
    private double radius;

    public Circle(double radius, String color) {
        super(color);
        this.radius = radius;
    }

    @Override
    public double getArea() {
        return Math.PI * radius * radius;
    }

    @Override
    public double getPerimeter() {
        return 2 * Math.PI * radius;
    }
}

class Square extends AbstractShape implements Shape{
    private double side;

    public Square(double side, String color){
        super(color);
        this.side = side;
    }

    @Override
    public double getArea(){
        return side * side;
    }

    @Override
    public double getPerimeter(){
        return 4 * side;
    }
}

public class Main {
    public static void main(String[] args) {
        Circle circle = new Circle(5, "red");
        Square square = new Square(4, "blue");
        System.out.println("Circle Area: " + circle.getArea());
        System.out.println("Square Perimeter: " + square.getPerimeter());
    }
}