How to swap or exchange objects in Java?

// Java program to demonstrate that we can swap two
// objects be swapping members

// Class 1
// Number class Car
class Car {
    // Attributes associated with car
    int no;
    Car(int no) { this.no = no; }
}

// Class 2
// Uses Car objects
class GFG {
    // Method 1
    // To swap
    public static void swap(Car c1, Car c2)
    {
        int temp = c1.no;
        c1.no = c2.no;
        c2.no = temp;
    }

    // Method 2
    // Main driver method
    public static void main(String[] args)
    {
        // Creating car class objects(creating cars)
        Car c1 = new Car(1);
        Car c2 = new Car(2);

        // Calling method 1
        swap(c1, c2);

        // Print and display commands
        System.out.println("c1.no = " + c1.no);
        System.out.println("c2.no = " + c2.no);
    }
}

// Java program to demonstrate that we can swap two
// objects be swapping members
// Where it does not work 

// Class 1
// A car with number and name
class Car {
     
    // Attributes of Car class 
    int model, no;

    // Constructor
    Car(int model, int no)
    {
      // This keyword is used to refer 
      // current instance itself
        this.model = model;
        this.no = no;
    }

    // Method of this class
    // To print Car
    void print()
    {
       // Printing number and model of car
        System.out.println("no = " + no +
                           ", model = " + model);
    }
}

// Class 2
// A class that uses Car
class Main
{
    // swap() doesn't swap c1 and c2
    public static void swap(Car c1, Car c2)
    {
        Car temp = c1;
        c1 = c2;
        c2 = temp;
    }

    // Driver method
    public static void main(String[] args)
    {
        Car c1 = new Car(101, 1);
        Car c2 = new Car(202, 2);
        swap(c1, c2);
        c1.print();
        c2.print();
    }
}

// Java program to Demonstrate that Wrapper Classes
// Can be Used to Swap two Objects

// Class 1
// A car with model and no.
class Car {
    // Attributes associated with car
    int model, no;

    // Constructor of class 1
    Car(int model, int no)
    {
        // This refers to current instance itself
        this.model = model;
        this.no = no;
    }

    // Method
    // To print object details
    void print()
    {
        System.out.println("no = " + no
                           + ", model = " + model);
    }
}

// Class 2
// Wrapper over class that is used for swapping
class CarWrapper {
    Car c;

    // Constructor
    CarWrapper(Car c) { this.c = c; }
}

// Class 3
// Uses Car class and swaps objects of Car
// using CarWrapper
class GFG {
    // This method swaps car objects in wrappers
    // cw1 and cw2
    public static void swap(CarWrapper cw1, CarWrapper cw2)
    {
        Car temp = cw1.c;
        cw1.c = cw2.c;
        cw2.c = temp;
    }

    // Main driver method
    public static void main(String[] args)
    {
        Car c1 = new Car(101, 1);
        Car c2 = new Car(202, 2);
        CarWrapper cw1 = new CarWrapper(c1);
        CarWrapper cw2 = new CarWrapper(c2);
        swap(cw1, cw2);
        cw1.c.print();
        cw2.c.print();
    }
}