Method overriding in java

Polymorphism is an important concept of object-oriented programming. It simply means more than one form. That is, the same entity (method or operator or object) can perform different operations in different scenarios. Example: Java Polymorphism class Polygon Output: Java Programming Language Common English Language In the above example, we have created a superclass named Language and a subclass named Java. Here, the method displayInfo() is present in both Language and Java. The use of displayInfo() is to print the information. However, it is printing different information in Language and Java. Based on the object used to call the method, the corresponding information is printed. Working of Java Polymorphism Note: The method that is called is determined during the execution of the program. Hence, method overriding is a run-time polymorphism. 2. Java Method Overloading In a Java class, we can create methods with the same name if they differ in parameters. For example, void func() Output: I am Programming Language. I am Object-Oriented Programming Language. In the above example, we have created an object variable pl of the ProgrammingLanguage class. Here, pl is a polymorphic variable. This is because, • In statement pl = new ProgrammingLanguage(), pl refer to the object of the ProgrammingLanguage class. • And, in statement pl = new Java(), pl refer to the object of the Java class.

Prerequisite: 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. This mechanism happens because the static method is resolved at the compile time. Static method bind during the compile time using the type of reference not a type of object. Output f1 method of the Complex class is executed. f1 method of the Complex class is executed. f2 method of the Complex class is executed. f2 method of the Sample class is executed. Difference Between Method Overriding and Method Hiding in Java • In method overriding both the method parent class and child class are non-static. • In method Hiding both the method parent class and child class are static. • In method Overriding method resolution is done on the basis of the Object type. • In method Hiding method resolution is done on the basis of reference type. • 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.

Example static int plusMethodInt(int x, int y) Instead of defining two methods that should do the same thing, it is better to overload one. In the example below, we overload the plusMethod method to work for both int and double: Example static int plusMethod(int x, int y)

Method Overriding Method overloading is a compile-time polymorphism. Method overriding is a run-time polymorphism. Method overloading helps to increase the readability of the program. Method overriding is used to grant the specific implementation of the method which is already provided by its parent class or superclass. It occurs within the class. It is performed in two classes with inheritance relationships. Method overloading may or may not require inheritance. Method overriding always needs inheritance. In method overloading, methods must have the same name and different signatures. In method overriding, methods must have the same name and same signature. In method overloading, the return type can or can not be the same, but we just have to change the parameter. In method overriding, the return type must be the same or co-variant. Static binding is being used for overloaded methods. Dynamic binding is being used for overriding methods. Poor Performance due to compile time polymorphism. It gives better performance. The reason behind this is that the binding of overridden methods is being done at runtime. Private and final methods can be overloaded. Private and final methods can’t be overridden. The argument list should be different while doing method overloading. The argument list should be the same in method overriding. Method Overloading in Java Compile time polymorphism. In method overloading, more than one method shares the same method name with a different signature...

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I have to create a lot of very similar classes which have just one method different between them. So I figured creating abstract class would be a good way to achieve this. But the method I want to override (say, method foo()) has no default behavior. I don't want to keep any default implementation, forcing all extending classes to implement this method. How do I do this? This is an excellent question for cases where you want ALL subclasses to call their parent. The answers so far seem to have not considered that case. Example: ensure a method needs to overridden in every class and call the parent: @override protected void importantMethod()