Method Overriding VS Method Overloading in Java: In this article, we will list the difference between method overriding and method overloading in Java. Before moving ahead with the differences, read the detailed concepts about method overloading and method overriding in the following articles
- Method Overriding in Java
- Method Overloading in Java
Let us detail out the difference between method overriding v/s method overloading in tabular form below
Method Overloading vs Method Overriding
| Method Overloading | Method Overriding |
| If any class contains multiple methods with an exact same name but with different input parameter list then it is known as method overloading | If a subclass has the same instance method with the same method signature as that of the super class’s method then it is said to be method overriding |
| Method name should be the same but with different number of input parameters or data-type of input parameters (includes order/sequence of input parameters) | Method signature should be same both in superclass as well as in subclass (including access modifier, return type & exception of method signature) |
| Method signature has to be different | Method signature should be the same |
| Input parameter lists have to be different | Input parameter lists should be the same even their data-types and order/sequence should the same |
| Overloading happens in the same class (just one class) | Overriding happens in 2 or more classes through inheritance concept |
| This provides multiple implementation version with same method name in the same class | This provides a specific implementation in subclass when extending from super class’s more general implementation |
| This is resolved at compile-time, therefore, it is also known as compile-time polymorphism | This is resolved at run-time, therefore, it is also known as run-time polymorphism |
| Sometimes, this is referred to as static binding as method call resolves during compilation | And this is referred to as dynamic binding as method calls resolve during execution |
| Method overloading increases the readability of the program | This is used to provides a specific implementation in the extending class |
| The return type can be the same or different in case of method overloading as it doesn’t get counted | Return type has to be same from that of super class’s return type (or else it should sub-class or sub-type of super class’s return type) This is called co-variant return type |
| Overloading gives better performance as it is resolved during a compile-time | Overriding performance is slightly on the lower side as compared to overloading |
| non-access modifiers like static or final aren’t get accounted in method overloadingTherefore, overloaded methods can have the static, final keyword in a method signature | Final methods cannot be overridden (this is inheritance concept)Static methods cannot be overridden, rather it can be re-declared in the subclass |
| Also, access modifiers like private aren’t get accounted in method overloading | Private methods cannot be overridden (again, this is inheritance concept) |
| Read method overloading rules | Read method overriding rules |
Example of Method Overloading
package in.bench.resources.java.overload;
public class TestJavaOverload {
void add(int num1, float num2) {
System.out.println("The summation of 2 numbers : " + (num1 + num2));
}
void add(int num1, float num2, int num3) {
System.out.println("The summation of 3 numbers : " + (num1 + num2 + num3));
}
public static void main(String args[]) {
TestJavaOverload t1 = new TestJavaOverload();
t1.add(12, 16f); // invoking 1st method with 2 arguments
t1.add(10, 20f, 30); // invoking 1st method with 3 arguments
}
}
Output:
The summation of 2 numbers : 28.0 The summation of 3 numbers : 60.0
Example of Method Overriding
Superclass
package in.bench.resources.method.overriding;
public class Shape {
void draw() throws Exception {
System.out.println("Super class >> Shape : draw() method");
}
}
Subclass
package in.bench.resources.method.overriding;
public class Circle extends Shape {
@Override
protected void draw() throws Exception {
System.out.println("Sub class >> Circle : draw() method");
}
}
