Thread: What is Method Overloading And Overriding In Java?

What is method overloading and overriding in Java?

Over-loading happens at compile-time while Overriding happens at runtime: The executed of bombarded technique contact to its meaning has happens at compile-time however executed of overridden technique contact to its meaning happens at playback.

The both methods required in java because:

The most primary distinction is that overloading is being done in the same category while for overriding platform and kid is required. Overriding is all about providing a particular execution to the got technique of mother or father category.

Fixed executed is being used for bombarded techniques and powerful executed is being used for overridden/overriding techniques.

Performance: Over-loading gives better efficiency in comparison to overriding. The reason is that the executed of overridden techniques is being done at playback.

2) In Technique Over-loading, Kinds of the same category stocks the same name but each method must have different variety of factors or factors having different kinds and purchase.

In Technique Overriding, sub category have the same method with same name and exactly the same kind and variety of factors and same come back kind as a extremely category.

Method Over-loading indicates more than one way stocks the same name in the category but having different trademark.

Method Overriding indicates way of platform category is re-defined in the produced category having same trademark.

Method Over-loading is an element that allows a category to have two or more techniques having same name, if their discussion details are different. In the last guide we mentioned constructor overloading that allows a category to have more than one constructors having different discussion details. Argument details could vary inMethod
Over-loading is an element that allows a category to have two or more
techniques having same name, if their discussion details are
different. In the last guide we mentioned constructor overloading
that allows a category to have more than one constructors having
different discussion details.
Argument
details could vary in –
1.
Variety of factors.
2.
Information kind of factors.
3.
Series of Information kind of factors.
Method
overloading is also known as Fixed Polymorphism.
Points
to Note:
1.
Fixed Polymorphism is also known as gather time executed or beginning
executed.
2.
Fixed executed happens at gather time. Method overloading is an
example of static executed where executed of method contact to its
meaning happens at Compile time.
java training

Method
Over-loading examples:
As
mentioned above, method overloading can be done by having different
discussion record. Allows see types of each and every situation.


Example
1: Over-loading – Different Variety of factors in discussion list
When
techniques name are same but variety of justifications are different.
class
DisplayOverloading
{
public
void disp(char c)
{
System.out.println(c);
}
public
void disp(char c, int num)
{
System.out.println(c
+ " "+num);
}
}
class
Sample
{
public
static void main(String args[])
{
DisplayOverloading
obj = new DisplayOverloading();
obj.disp('a');
obj.disp('a',10);
}
}
Output:

a
a
10
In the above example – method disp() has been overloaded based on the quantity of justifications – We have two meaning of method disp(), one with one discussion and another with two justifications.

Stating a method in subclass which is already present in parent class is known as method overriding. Previously we distributed strategy over-loading in Java. In this guide we will see strategy overriding with illustrations.

Example:

One of the easiest example – Here Boy class expands Human c;ass. Both the sessions have a common method void eat(). Boy category is giving its own execution to the eat() strategy or in other words it is overriding the process eat().

class
Human{
public void eat()
{
System.out.println("Human is
eating");
}
}
class Boy extends Human{
public void eat(){
System.out.println("Boy is eating");
}
public static void main( String args[]) {
Boy obj = new Boy();
obj.eat();
}
}
Output:

Boy is eating
Advantage of method overriding

The main benefits of strategy overriding is that the category can give its own specific execution to a got strategy without even changing the mother or father class(base class).

Method Overriding in powerful strategy dispatch

Dynamic strategy delivery is a strategy which allows us to allocate the bottom category referrals to children category item. As you can see in the below example that the bottom category referrals is allocated to kid category item.

Method Over-loading is an element that allows a category to have two or more techniques having same name, if their discussion details are different. In the last guide we mentioned constructor overloading that allows a category to have more than one constructors having different discussion details. Argument details could vary inMethod
Over-loading is an element that allows a category to have two or more
techniques having same name, if their discussion details are
different. In the last guide we mentioned constructor overloading
that allows a category to have more than one constructors having
different discussion details.
Argument
details could vary in –
1.
Variety of factors.
2.
Information kind of factors.
3.
Series of Information kind of factors.
Method
overloading is also known as Fixed Polymorphism.
Points
to Note:
1.
Fixed Polymorphism is also known as gather time executed or beginning
executed.
2.
Fixed executed happens at gather time. Method overloading is an
example of static executed where executed of method contact to its
meaning happens at Compile time.
java training

Method
Over-loading examples:
As
mentioned above, method overloading can be done by having different
discussion record. Allows see types of each and every situation.


Example
1: Over-loading – Different Variety of factors in discussion list
When
techniques name are same but variety of justifications are different.
class
DisplayOverloading
{
public
void disp(char c)
{
System.out.println(c);
}
public
void disp(char c, int num)
{
System.out.println(c
+ " "+num);
}
}
class
Sample
{
public
static void main(String args[])
{
DisplayOverloading
obj = new DisplayOverloading();
obj.disp('a');
obj.disp('a',10);
}
}
Output:

a
a
10
In the above example – method disp() has been overloaded based on the quantity of justifications – We have two meaning of method disp(), one with one discussion and another with two justifications.

Stating a method in subclass which is already present in parent class is known as method overriding. Previously we distributed strategy over-loading in Java. In this guide we will see strategy overriding with illustrations.

Example:

One of the easiest example – Here Boy class expands Human c;ass. Both the sessions have a common method void eat(). Boy category is giving its own execution to the eat() strategy or in other words it is overriding the process eat().

class
Human{
public void eat()
{
System.out.println("Human is
eating");
}
}
class Boy extends Human{
public void eat(){
System.out.println("Boy is eating");
}
public static void main( String args[]) {
Boy obj = new Boy();
obj.eat();
}
}
Output:

Boy is eating
Advantage of method overriding

The main benefits of strategy overriding is that the category can give its own specific execution to a got strategy without even changing the mother or father class(base class).

Method Overriding in powerful strategy dispatch

Dynamic strategy delivery is a strategy which allows us to allocate the bottom category referrals to children category item. As you can see in the below example that the bottom category referrals is allocated to kid category item.

Hello,

Overriding/Overloading in java is more then just saying:

Overridden version of the method to call (in other words, from which class in the inheritance tree) is decided at runtime based on object type, but which overloaded version of the method to call is based on the reference type of the argument passed at compile time.

The above statement itself it is not enough to illustrate all the aspects of this topic.

Here are the rules for Overriding/Overloading from OCA Java® SE 8 Programmer I Exam Guide - Oracle Press:

Overriding and Overloading (OCA Objectives 6.1 and 7.2)
☐ Methods can be overridden or overloaded; constructors can be overloaded but not overridden.
☐ With respect to the method it overrides, the overriding method
☐ Must have the same argument list
☐ Must have the same return type or a subclass (known as a covariant return)
☐ Must not have a more restrictive access modifier
☐ May have a less restrictive access modifier
☐ Must not throw new or broader checked exceptions
☐ May throw fewer or narrower checked exceptions, or any unchecked exception
☐ final methods cannot be overridden.
☐ Only inherited methods may be overridden, and remember that private
methods are not inherited.
☐ A subclass uses super.overriddenMethodName() to call the superclass version of an overridden method.
☐ A subclass uses MyInterface.super.overriddenMethodName() to call the super interface version on an overridden method.
☐ Overloading means reusing a method name but with different arguments.
☐ Overloaded methods
☐ Must have different argument lists
☐ May have different return types, if argument lists are also different
☐ May have different access modifiers
☐ May throw different exceptions
☐ Methods from a supertype can be overloaded in a subtype.
☐ Polymorphism applies to overriding, not to overloading.
☐ Object type (not the reference variable's type) determines which overridden method is used at runtime.
☐ Reference type determines which overloaded method will be used at compile time.

Regards
Alin

There are many differences between method overloading and method overriding in java. A list of differences between method overloading and method overriding are given below:

No.
Method Overloading
Method Overriding

1)
Method overloading is used to increase the readability of the program.
Method overriding is used to provide the specific implementation of the method that is already provided by its super class.

2)
Method overloading is performed within class.
Method overriding occurs in two classes that have IS-A (inheritance) relationship.

3)
In case of method overloading, parameter must be different.
In case of method overriding, parameter must be same.

4)
Method overloading is the example of compile time polymorphism.
Method overriding is the example of run time polymorphism.

5)
In java, method overloading can't be performed by changing return type of the method only. Return type can be same or different in method overloading. But you must have to change the parameter.
Return type must be same or covariant in method overriding.

Java Method Overloading example



class OverloadingExample{
static int add(int a,int b){return a+b;}
static int add(int a,int b,int c){return a+b+c;}
}
Java Method Overriding example



class Animal{
void eat(){System.out.println("eating...");}
}
class Dog extends Animal{
void eat(){System.out.println("eating bread...");}
}

Overloading occurs when two or more methods in one class have the same method name but different parameters.


Overriding means having two methods with the same method name and parameters (i.e., method signature). One of the methods is in the parent class and the other is in the child class. Overriding allows a child class to provide a specific implementation of a method that is already provided its parent class.


2. Overriding vs. Overloading

Here are some important facts about Overriding and Overloading:

1). The real object type in the run-time, not the reference variable's type, determines which overridden method is used at runtime. In contrast, reference type determines which overloaded method will be used at compile time.
2). Polymorphism applies to overriding, not to overloading.
3). Overriding is a run-time concept while overloading is a compile-time concept.

3. An Example of Overriding

Here is an example of overriding. After reading the code, guess the output.

class Dog{
public void bark(){
System.out.println("woof ");
}
}
class Hound extends Dog{
public void sniff(){
System.out.println("sniff ");
}

public void bark(){
System.out.println("bowl");
}
}

public class OverridingTest{
public static void main(String [] args){
Dog dog = new Hound();
dog.bark();
}
}
Output:

bowl
In the example above, the dog variable is declared to be a Dog. During compile time, the compiler checks if the Dog class has the bark() method. As long as the Dog class has the bark() method, the code compilers. At run-time, a Hound is created and assigned to dog. The JVM knows that dog is referring to the object of Hound, so it calls the bark() method of Hound. This is called Dynamic Polymorphism.

4. An Example of Overloading

class Dog{
public void bark(){
System.out.println("woof ");
}

//overloading method
public void bark(int num){
for(int i=0; i<num; i++)
System.out.println("woof ");
}
}
In this overloading example, the two bark method can be invoked by using different parameters. Compiler know they are different because they have different method signature (method name and method parameter list).