Prime number

import javax.swing.JOptionPane;

public class Prima {
public static void main (String [] args) {
String numString;
int numInt;
int i;
int jum=0;

numString = JOptionPane.showInputDialog("Masukkan Angka Bilangan Prima : ");
numInt = Integer.parseInt(numString);

for (i=1 ; i<=numInt ; i++){
if (numInt % i == 0) {
jum = jum + 1;
}
}

if (jum==2 && numInt !=1){
JOptionPane.showMessageDialog(null, "Bilangan Prima","Pesan",1);
}

else{JOptionPane.showMessageDialog(null, "Bukan Bilangan Prima","Pesan",1);
}
}
}