When a method in a subclass has the same name and type signatures as a method in the superclass?
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A subclass inherits all public methods from its superclass, and these methods remain public in the subclass. But, we also usually add more methods or instance variables to the subclass. Sometimes, we want to modify existing inherited methods. This is called overriding methods. Overriding an inherited method means providing a public method in a subclass with the same method signature (method name, parameter type list and return type) as a public method in the superclass. The method in the subclass will be called instead of the method in the superclass. One common method that is overridden is the toString() method. The example below shows a similar method called greet().  In the following example the MeanGreeter inherits the greet() method from Greeter, but then overrides it. Run the program to see. Add another subclass called SpanishGreeter (or another language that you know) that extends Greeter and override the greet() method to return Hola! (or hi in another language) instead of Hi!. Create an object to test it out. Note To override an inherited method, the method in the child class must have the same name, parameter list, and return type (or a subclass of the return type) as the parent method. Any method that is called must be defined within its own class or its superclass. You may see the @Override annotation above a method. This is optional but it provides an extra compiler check that you have matched the method signature exactly. @Override public String greet() { return "Go Away"; } 9.3.1. Overloading Methods¶Don’t get overriding a method confused with overloading a method! Overloading a method is when several methods have the same name but the parameter types, order, or number are different. So with overriding, the method signatures look identical but they are in different classes, but in overloading, only the method names are identical and they have different parameters. // overriding methods g2.greet(); // This could be calling an overridden greet method in g2's class g1.greet("Sam"); // This calls an overloaded greet method In the example below the greet(String who) method overloads the greet() method of Greeter. Notice that MeanGreeter inherits this method and it isn’t overridden. After running the code, try overriding the greet(String) method in the MeanGreeter class to return Go away + the who String. Note To overload a method the method must have the same name, but the parameter list must be different in some way. It can have a different number of parameters, different types of parameters, and/or a different order for the parameter types. The return type can also be different.
9-3-3: Which of the following declarations in Student would correctly override the getFood method in Person?
You can step through an example of this in the Java Visualizer by clicking on the following link Override Example.
9-3-4: Which of the following declarations in Person would correctly overload the getFood method in Person?
You can step through an example of this using the Java Visualizer by clicking on the following link Overload Example. What happens if you change the main method in the Java Visualizer to create a new Student object instead of a Person object? Does it still print the same thing? 9.3.2. Inherited Get/Set Methods¶Inheritance means that an object of the child class automatically includes the object instance variables and methods defined in the parent class. But, if the inherited instance variables are private, which they should be, the child class can not directly access the them using dot notation. The child class can use public accessors (also called getters or get methods) which are methods that get instance variable values and public mutators (also called modifier methods or setters or set methods) which set their values. For example, if a parent has a private instance variables, name, then the parent typically provides a public getName method and a public setName method as shown below. In the setName method below, the code checks if the passed string is null before it sets it and returns true if the set was successful or false otherwise. The Employee class inherits the name field but must use the public method getName and setName to access it. Demonstrated inherited get/set methods.
9-3-6: Given the following class definitions which of the following would not compile if it was used in place of the missing code in the main method? class Item { private int x; public void setX(int theX) { x = theX; } // ... other methods not shown } public class EnhancedItem extends Item { private int y; public void setY(int theY) { y = theY; } // ... other methods not shown public static void main(String[] args) { EnhancedItem currItem = new EnhancedItem(); // missing code } } You can step through this code in the Java Visualizer by clicking on the following link Private Fields Example. 9.3.3. Programming Challenge : Pet Sounds¶The following Pet class keeps track of a pet’s name and type and has a constructor, get method, and a method called speak() that prints an animal noise.
Complete the Dog and Cat classes below to inherit from Pet with a constructor and a method speak() that prints out Woof! or Meow!. 9.3.4. Summary¶
You have attempted of activities on this page Can a subclass have a method with the same name and the same signature as its superclass?If your subclass defines a method with the same name and signature as a method in its superclass, the method in the subclass overrides the one in the superclass. Thus, the subclass does not inherit the method from its superclass.
When a method in a subclass has the same name and return type as method in superclass it is known as?When a method in a subclass has the same name, same parameters or signature, and same return type(or sub-type) as a method in its super-class, then the method in the subclass is said to override the method in the super-class. Method overriding is one of the way by which java achieve Run Time Polymorphism.
Will a method in a subclass with the same signature as a method in a superclass with a different return type cause any problem?11.14 If a method in a subclass has the same signature as a method in its superclass with a different return type, will this be a problem? It will be a syntax error.
What is the process of defining a method in subclass having same name and type signature Mcq?2. What is the process of defining a method in a subclass having same name & type signature as a method in its superclass? Explanation: None.
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