java对象赋值另一对象成员

简单的内存知识，生疏了，为了稳妥又测试了一下……

public class TryCopy {
    public static void main(String[] args) {
        Point a = new Point(1, 2);
        Point b = new Point(3, 4);
        Line temp = new Line(a, b);
        a.setX(100);
        System.out.println(temp.s.x);
    }
}

class Line {
    Point s;
    Point e;
    public Line(Point a, Point b) {
        this.s = a;
        this.e = b;
    }
}

class Point {
    int x;
    int y;
    public void setX(int x) {
        this.x = x;
    }
    public Point(int x, int y) {
        this.x = x;
        this.y = y;
    }
}

输出结果：

100