Method Overloading in Java with examples
Method Overloading is a feature that allows a class to have more than one method having the same name, if their argument lists are different. It is similar to constructor overloading in Java, that allows a class to have more than one constructor having different argument lists.
let’s get back to the point, when I say argument list it means the parameters that a method has: For example the argument list of a method add(int a, int b) having two parameters is different from the argument list of the method add(int a, int b, int c) having three parameters.
Three ways to overload a method
In order to overload a method, the argument lists of the methods must differ in either of these:
1. Number of parameters.
For example: This is a valid case of overloadingadd(int, int)
add(int, int, int)
2. Data type of parameters.
For example:add(int, int)
add(int, float)
3. Sequence of Data type of parameters.
For example:add(int, float)
add(float, int)
Invalid case of method overloading:
When I say argument list, I am not talking about return type of the method, for example if two methods have same name, same parameters and have different return type, then this is not a valid method overloading example. This will throw compilation error.int add(int, int)
float add(int, int)
Method overloading is an example of Static Polymorphism. We will discuss polymorphism and types of it in a separate tutorial.
Points to Note:
1. Static Polymorphism is also known as compile time binding or early binding.
2. Static binding happens at compile time. Method overloading is an example of static binding where binding of method call to its definition happens at Compile time.
Method Overloading examples
As discussed in the beginning of this guide, method overloading is done by declaring same method with different parameters. The parameters must be different in either of these: number, sequence or types of parameters (or arguments). Lets see examples of each of these cases.
Argument list is also known as parameter list
Example 1: Overloading – Different Number of parameters in argument list
This example shows how method overloading is done by having different number of parametersclass 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() is overloaded based on the number of parameters – We have two methods with the name disp but the parameters they have are different. Both are having different number of parameters.
Example 2: Overloading – Difference in data type of parameters
In this example, method disp() is overloaded based on the data type of parameters – We have two methods with the name disp(), one with parameter of char type and another method with the parameter of int type.class DisplayOverloading2 { public void disp(char c) { System.out.println(c); } public void disp(int c) { System.out.println(c ); } } class Sample2 { public static void main(String args[]) { DisplayOverloading2 obj = new DisplayOverloading2(); obj.disp(‘a’); obj.disp(5); } }
Output:a 5
Thanking You
Tech Jitendra
Tech Jitendra 