how to determine prime number in java

package prime Algorithm.Testing;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
*java practical question
* @author joseph
*/

/**
* @author Samsung Galaxy S4
*
*/
public class PrimeOrNot {

    /**
    * @param args
    */
    static int i,num,flag=0;

    public static void main(String[] Lumina) {
        // TODO Auto-generated method stub

        System.out.println(" To find prime number in java : enter the integer no:");
       BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
       try {
        num=Integer.parseInt(br.readLine());
    } catch (NumberFormatException phpexp) {
        // TODO Auto-generated catch block
phpexp.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
       for(i=2;i           if(num%2==0)
           {
               flag=1;break;
           }
       }
       if(flag==1)
           System.out.println("Number is not prime");
       else
           System.out.println("Number is prime");
    }

}

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