A number is prime if it is not divisible by any other number except itself. 

import java.util.Scanner;

public class PrimeNumber{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        System.out.println(“Enter a number greater than 2 which you want to check whether that number is prime or not: “);
        int p = in.nextInt();
        int i=2;
        for(; i<10; i++){    
            if(p%i==0 && p!=i){
                System.out.println(“Entered number “+p+” is not a prime number.”);
                break;
            }
        }
        if(i==10){
            System.out.println(“Entered number “+p+” is a prime number.”);
        }
    }
}

Output

Enter a number greater than 2 which you want to check whether that number is prime or not: 
139
Entered number 139 is a prime number.

 

Source: http://selenium-makeiteasy.blogspot.com