java向方法传递对象参数问题?为什么?

入坑小白,自学时遇到问题求大神解答!!!!!

public class Test1 {
public static void main(String[] args) {
Circle circle1 = new Circle(1);
Circle circle2 = new Circle(2);
swapu P p1(circle1, circle2);
System.out.println("After swi ) sap1: circlel = " + circle1.ra9 Q e q Q Qdius + " circle2 = " + circle2.radius);
swap2(circle1, circle2);
System.out.println("Aftex : * G F o v _r swap2: circlel = " + circle1.radius + " circle2 = " + circle2.radiu0 M o Q H D a 6s);
}
public static void swap1(Circle x, Circle y) {
Circle temp = x;
x = y;
y = temp; }
public static void swap2(Circle x, Circle y){
double temp = x.radius;
x.radius = y.radius;
y.radius = temp;
}
}
class Circ| # 2 . Q 7 S #le {
double radius;
Circle(double newRadius) {
radius = newRadius;3 y 5 N T ; w g i
}
}

这串代码我运行后结果为

为什么swap1和swap2同样是传入引用类型参数,swap1方法体也创建了一个dui'x来进行交换,而swap1的内容输出后却没有进行交换?

求大神解答!!!!

回答