Overwrite - METHOD, PARAMS

Week 5: Class hierarchies/07A. Overwrite and override [Overwrite - METHOD, PARAMS]

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+An essential part of specialisation in the child classes is the MODIFICATION of the FUNCTIONALITY inherited from the parent class. 
+In other words, a child class can either ADD completely new features or MODIFY inherited features.
+
+Implementing an inherited method in a new child class is called OVERWRITING the method.
+
+To overwrite a method, it is sufficient to implement the corresponding method in the inherited class. 
+In this case, the objects created from the inherited class will automatically use the 'newer' implementation. 
+The method to be overwritten must therefore have 
+- the SAME NAME as the original method, and
+- the same list of PARAMETERS as the original method. 
+
+
+The NUMBER, TYPE and ORDER of PARAMETERS must therefore be exactly the same. 
+The name of the formal parameters is irrelevant in this context.
+
+As a simple example, consider the class Dog with the method bark:
+class Dog {
+    public void bark() {
+        System.out.println("Bark!");
+    }
+}
+ 
+
+Let's then write a child class of the Dog class BigDog, with a reimplemented or overwritten barking method:
+class BigDog extends Dog {
+    public void bark() {
+        System.out.println("WOOF WOOF!");
+    }
+}
+ 
+
+The version of the method used now depends on the type of object being created:
+public static void main(String[] args) {
+    Random r = new Random();
+    
+    Dog snoopy = new Dog();
+    BigDog cerberus = new BigDog();
+    
+    snoopy.bark();
+    cerberus.bark();
+}
+ 
+
+Program outputs:
+Bark!
+WOOF WOOF!
+
+
+
+
+