Also there is no issue if subclass overridden method is not throwing any exception. In Java, methods are virtual by default. We can have multilevel method-overriding. Overloading is an example of compiler-time polymorphism and overriding is an example of run time polymorphism. Why Method Overriding?
As stated earlier, overridden methods allow Java to support run-time polymorphism. Polymorphism is essential to object-oriented programming for one reason: it allows a general class to specify methods that will be common to all of its derivatives while allowing subclasses to define the specific implementation of some or all of those methods.
Dynamic Method Dispatch is one of the most powerful mechanisms that object-oriented design brings to bear on code reuse and robustness. The ability to exist code libraries to call methods on instances of new classes without recompiling while maintaining a clean abstract interface is a profoundly powerful tool. Overridden methods allow us to call methods of any of the derived classes without even knowing the type of derived class object.
When to apply Method Overriding? Used correctly, the superclass provides all elements that a subclass can use directly. It also defines those methods that the derived class must implement on its own. This allows the subclass the flexibility to define its methods, yet still enforces a consistent interface.
Thus, by combining inheritance with overridden methods, a superclass can define the general form of the methods that will be used by all of its subclasses. Consider an employee management software for an organization, let the code has a simple base class Employee, the class has methods like raiseSalary , transfer , promote ,..
Different types of employees like Manager, Engineer,.. In our complete software, we just need to pass a list of employees everywhere and call appropriate methods without even knowing the type of employee. You will get a compile-time error if you attempt to change an instance method in the superclass to a static method in the subclass, and vice versa.
The following table summarizes what happens when you define a method with the same signature as a method in a superclass. All rights reserved. Hide TOC. Interfaces and Inheritance. Multiple Inheritance of State, Implementation, and Type. Instance Methods An instance method in a subclass with the same signature name, plus the number and the type of its parameters and return type as an instance method in the superclass overrides the superclass's method.
Static Methods If a subclass defines a static method with the same signature as a static method in the superclass, then the method in the subclass hides the one in the superclass. The distinction between hiding a static method and overriding an instance method has important implications: The version of the overridden instance method that gets invoked is the one in the subclass. The version of the hidden static method that gets invoked depends on whether it is invoked from the superclass or the subclass.
Note: In a subclass, you can overload the methods inherited from the superclass. But yeah, true, but not a complete answer. I have gone through many answers and articles but this is what i found is, — sanju. Override method use with example is explained below. Check the below code where, 1. The Swift car isn't overriding anything — OneCricketeer. The Overflow Blog. Does ES6 make JavaScript frameworks obsolete?
Podcast Do polyglots have an edge when it comes to mastering programming Featured on Meta. Then, at the runtime, it runs the method specific for that object. This program will throw a compile time error since b's reference type Animal doesn't have a method by the name of bark. The return type should be the same or a subtype of the return type declared in the original overridden method in the superclass.
The access level cannot be more restrictive than the overridden method's access level. For example: If the superclass method is declared public then the overridding method in the sub class cannot be either private or protected.
A subclass within the same package as the instance's superclass can override any superclass method that is not declared private or final.
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