Notes

1. 08/08/2025 1
A Presentation on Method Overloading
and Method Overriding
Presented By
Md. Rayhanul Islam
Institute of Information Technology
University of Dhaka

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Outline
What is Method?
Parts of Method
Method Overloading
Example of Method Overloading
Method Overriding
Example of Method Overriding
Rules for Method Overriding

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What is Method?
A collection of statements that are grouped together to perform an operation
A method has the following syntax:
modifier return_Value_Type Method_Name(list of parameters){
// Method body;
}

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Parts of Method
1. Modifiers:
 Tells the compiler how to call the method
 Defines the access type of the method
2. Return Types
 The data type of the value the method returns
 The return type void when no value is returned

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Parts of Method (Cont…)
Method Name
The actual name of the method
Method name and the parameter list together constitute the method signature
Parameters
When a method is invoked, a value is passed to parameter
This value is referred to as actual parameter or argument
The parameter list refers to the type, order, and number of the parameters

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Parts of Method (Cont…)
Method Body
The method body contains a collection of statements that define what the method does

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Method Overloading
Method with same name but different behavior
Method with same but different method signature
Overloaded methods may or may not have different return type but it should have different
argument(s)
int test (){ }
int test(int a){ }
int test(double a){ }
int test (double a, int a){ }

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Code Example
public class MethodOverloading {
// Method 1
public int Addition(int a, int b) {
System.out.println(“Method 1 is called”);
return a + b;
}
// Method 2
public int Addition(int a, int b, int c) {
System.out.println(“Method 2 is called”);
return a + b + c;
}
}

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Code Example (Cont…)
public static void main( String[]args ) {
int Answer1 = Addition(5, 6);
// In this case Method 1 will be called
System.out.println(“Answer 1 = ” + Answer1);
System.out.println(“----------------------------”);
int Answer2 = Addition(5, 6, 7);
// In this case Method 2 will be called
System.out.println(“Answer 2 = ” + Answer2);
}

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Output
Output of the code
Method 1 is called
Answer 1 = 11
----------------------------
Method 2 is called
Answer 2 = 18

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Method Overriding
 The child class provides alternative implementation for parent class method.
 The key benefit of overriding is the ability to define behavior that's specific to a particular
subclass type.
 Overridden method: In the superclass.
 Overriding method: In the subclass.

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Example of Method Overriding
public class Car {
public void maxSpeed(){
System.out.println("Max speed is 60 mph");
}
}
class Ferrari extends Car{
public void maxSpeed() {
System.out.println("Max speed is 120 mph");
}
public void msc(){}
}

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Method Overriding
 public class TestCar
{
 public static void main(String args[]){
 Ferrari f=new Ferrari();
 f.maxSpeed();
 }
 OR
 public static void main(String args[]){
 Car f=new Ferrari();
 f.maxSpeed();
 }
 }

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Rules for Method Overriding
EXACT argument list matching
public class Car{
public void maxSpeed(int speed){
System.out.println("Max speed is ” +speed+ “ mph");
}
}
class Ferrari extends Car{
public void maxSpeed(float speed){
System.out.println("Max speed is ” +speed+ “ mph");
}
public void msc(){}
}

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Rules for Method Overriding
The return type must be the same as, or subtype of the return type declared in the
parent class
class Alpha {
Alpha doStuff(char c) {
return new Alpha();
}
}
class Beta extends Alpha {
Beta doStuff(char c) {
return new Beta();
}
}

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Rules for Method Overriding
Possible only through Inheritance
public class Car {
protected void maxSpeed(){
System.out.println("Max speed is 60 mph");
}
}
class Ferrari {
public void maxSpeed(){
System.out.println("Max speed is 120 mph");
}
public void msc(){}
}

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Thank you
Although these two terms sound similar but distinct in meaning.
For more information:
The Complete Reference by Herbert Schildt
Starting out with C++ by Tony Gaddis