Java Swap

gistfile1.java

class A {
    private String name = null;
    public A(String newName) {
        name = newName;
    }
    public void Assign(A other) {
        name = other.name;
    }
    public void SayHi() {
        System.out.println("Hello from " + name);
    }
}


class TestSwap {
    public static void swap(A a1, A a2) {
        A temp = new A("");
        temp.Assign(a1);
        a1.Assign(a2);
        a2.Assign(temp);
    }

    public static void setA3ByValue() {
        A a1 = new A("Dog");
        A a2 = new A("Cat");
        A a3 = new A("");
        a3.Assign(a1);
        swap(a1,a2);
        a1.SayHi();
        a2.SayHi();
        a3.SayHi();
    }

    public static void setA3ByReference() {
        A a1 = new A("Dog");
        A a2 = new A("Cat");
        A a3 = a1;
        swap(a1,a2);
        a1.SayHi();
        a2.SayHi();
        a3.SayHi();
    }
    public static void main(String[] args) {
        setA3ByValue();
        setA3ByReference();
    }
}