Check Prime Numbers
  
 Source Code
  

    
// Contributed by - Anuj Das ( GC College, Silchar - @ Department of Computer Science )
import java.util.Scanner;

class CheckPrime {
  public static void main(String[] args) {
      System.out.print("Enter an Integer:  ");
      int x = new Scanner(System.in).nextInt();

      if(x == 1) {
          System.out.println(x + " is neither Prime nor Composite!");
          return;
      }
      else {
          for(int i=2; i <= x/2; i++) {
              if(x%i == 0) {
                  System.out.println(x + " is not a Prime Number!");
                  return;
              }
          }
          System.out.println(x + " is a Prime Number!");
      }
  }
}

    

cmd->  javac  CheckPrime.java
cmd->  java  CheckPrime

Enter an Integer:  15
15 is not a Prime Number!


Enter an Integer:  1
1 is neither Prime nor Composite!


Enter an Integer:  5
5 is a Prime Number!