Program to check number is prime or not.

import java.io.*;
class PrimeNum
{
public static void main(String args[])
{
int num,i,flag=0;
DataInputStream r = new DataInputStream(System.in);
try
{
System.out.println("Enter the number:");
num = Integer.parseInt(r.readLine());
for(i=2;i<num;i++)
{
if(num%i==0)
{
flag = flag+1;
break;
}
}
if(flag==0)
{
System.out.println("Number is Prime");
}
else
{
System.out.println("Number is not Prime");
}
}
catch(Exception e)
{
System.out.println("error is occur in = "+e);
}
}
}