Method Overriding Rules

Method override occurs when a class has multiple derived classes and the derived classes must use the methods of its parent class with the same signature (number, type, and parameter order) but with a different implementation. Reason: At compile time, the reference type check is performed. However, at run time, JVM determines the object type and executes the method that belongs to that particular object. This is also correct, there are no restrictions on throwing an unchecked exception for the parent method. Let`s look at a more practical example that uses method override. Imagine an employee management software for an organization, let the code have a simple base class Employee, the class has methods like raiseSalary(), transfer(), promote(),. etc. Different types of employees such as manager, engineer,. and so on.

may have their implementations of methods present in the Employee base class. In our complete software, simply pass a list of employees everywhere and call the appropriate methods without knowing the type of employee. For example, we can easily increase the salary of all employees by going through the list of employees. Any type of employee can have his logic in his class, we do not have to worry because if raiseSalary() exists for a certain type of employee, only this method would be called. The override method in the subclass can throw any unchecked (run) exception, regardless of whether the overridden method in the parent class declares the exception. Method Override is a function that allows us to redefine the method in the subclass or derived class that is already defined in its parent class or superclass. In any object-oriented programming language, replacement is a feature that allows a subclass or child class to provide a specific implementation of a method already provided by one of its parent classes or classes. If a method in a subclass has the same name, parameters, or signature and returns the same type (or subtype) as a method in its parent class, the method of the subclass replaces the method of the parent class. If we call the displayInfo() method with object d1 of the Dog subclass, the method is called in the Dog subclass. The method within the superclass is not called. There is no effect on the superseded method if the method is declared synchronized or strictfp in the superclass.

If two or more independently defined standard methods conflict, or if a standard method conflicts with an abstract method, the Java compiler generates a compiler error. You must explicitly override supertype methods. Please also add rules of the return type in the singnature method. We can change the access modifier for a parent method. In the derived class, when we replace a method, we can provide less restrictive but no more restrictive access than the substituted method access to the superclass. The same method declared in the superclass and its subclasses may have different access identifiers. However, there is one caveat. This statement must call method1 of the child class, but because the child class replaces the method with the static keyword, this method is hidden and method1 of the parent class is called. The problem is that I have to provide a specific implementation of the run() method in a subclass, which is why we use method override. We can only replace Java abstract methods in concrete classes, otherwise a compilation error will occur.

A concrete class is a class that has the implementation of all its methods. Simply put, classes that do not have abstract methods are called concrete classes. Please see the following code.class UNIX { protected final void whoAmI() { System.out.println(“I am UNIX”); } protected final void whoAmI(String name, String i) { System.out.println(“I am ” + name); } protected final void whomAmI(String i, String name) { System.out.println(“Trial on Reversing the arguments without change the datatypes”); } } public class MethodOverloading { public static void main(String args[]) { UNIX unix = new UNIX(); unix.whoAmI(“Sr”,”Madhu”); }} Here is the output I am Sri, how does the compiler only call this particular method? and why I don`t get an error like an inaccessible code or something like that. Thanks in advance. Sincerely, Madhu. For example, we cannot override a method that declares a SQLException. An exception or other non-executed exception that is overridden by a method that declares a FileNotFoundException, unless it is a subclass of FileNotFoundException. In Java, abstract classes are created to be the superclass of other classes. And if a class contains an abstract method, it must be replaced. Consider an example that contains two classes. The first is Animal, which contains an instance method and a static method: if a subclass defines a static method with the same signature as a static method in the superclass, the subclass method hides the method in the superclass.

When calling a superclass version of an overridden method, the super keyword is used. Please update the return type rule in the method signature asThe return type of the replacement method must be the same as the return type of the superclass, or it can be a subtype of the superclass return type. Now, if the same method is defined in both the superclass and subclass, the method of the subclass class overrides the method of the superclass. This is called method replacement. Part of the key to the successful application of polymorphism is the understanding that superclasses and subclasses form a hierarchy that moves from a smaller specialization to a larger one. When used correctly, the superclass provides all the elements that a subclass can use directly. It also defines the methods that the derived class should implement on its own. This gives the subclass the flexibility to define its methods while forcing a consistent interface.

By combining inheritance with superseded methods, a superclass can define the general form of methods used by all subclasses. For example, suppose a myClass() method of the superclass is declared protected.