Object as Parameter

In Java, the object can serve as parameter from a method. So far we are only using variables with simple type as parameters that we pass into a method. In this post we will see how Java treats the object as a parameter. To simplify the discussion, here we will add a method to the class Box containing the parameter of object. The method we will use to compare the box object with each other, whether equal or not. The source code is as follows:

class Box {
   double length;
   double width;
   double height;

   Box (double l, double w, double h) {
      length = l;
      width = w;
      height = h;
   }

   double calculateVolume() {
      return(length * width * height);
   }

   //Define method with object Box as parameter 
   boolean isSame(Box k) {
      if ((k.length == this .length) &&
         (k.width == this.width) &&
         (k height == this.height)) {
         return true;
      } else {
  return false;
      }
   }
}

class DemoParamObject {

   public void main(String [] args) {

      Box b1, b2, b3, b4;

      b1 = new Box(4, 3, 2); 
      b2 = new Box(6, 5, 4); 
      b3 = new Box(4, 3, 2); 
      b4 = new Box(6, 5, 4);

      System.out.println ("b1 == b2 : " + b1.isSame(b2)); 
      System.out.println ("b1 == b3 : " + b1.isSame(b3)); 
      System.out.println ("b2 == b4 : " + b2.isSame(b4));
   }
}

The result will be given by the above program as follows:

b1 == b2: false
b1 == b3: true
b2 == b4: true

Method isSame() that you see above has box object as parameter. Please also be noted how to call:

b1.isSame(b2)

The above code is used to check whether the object b1 and b2 is equal to or not. If the value of both object is same, the method will return true. Otherwise, the value to be returned is false.