void and Void

 

void is a keyword which is used to specify the return type of a method.When a method return type is void,it means,the method is not going to return anything

Void is a class with private constructor,Hence we cannot create the object of such class.

What is the Use of Void class?
It is use to know the return type of a method,via reflection api.
Assume you have a Demo class with a show() method

public class Demo
{
public void show(){}
}

Now Based on the return type(If return type is void do something) else do someother thing
So the code to find out the return type is

Class c1 =Demo.class.getMethod("show",null).getReturnType(); 
 if(c1 == Void.TYPE)
{
//Some Business logic when return type is void
}

The complete program is
VoidDemo.java

import java.util.List;

class Demo
{
    public void show()
    {
        
    }
}


public class VoidDemo {
    public static void main(String[] args) throws NoSuchMethodException,SecurityException {
        Class c1 = Demo.class.getMethod("show",null).getReturnType();
        
        if(c1 == Void.TYPE){
        System.out.println("Void return type");}
        else{
        System.out.println("Something was returned");}
        
    }
}

Output:-
Void return type