Kodingan Sederhana mencari Nilai Rata - rata pada Java

Kodingan :

import javax.swing.JOptionPane;
public class Nilai{
  public static void main( String[] args ){
    String a= "";
    String b= "";
    String c= "";
    a= JOptionPane.showInputDialog("Input Nilai Pertama");
    int n1= Integer.valueOf(a).intValue();
    b= JOptionPane.showInputDialog("Input Nilai Kedua");
    int n2= Integer.valueOf(b).intValue();
    c= JOptionPane.showInputDialog("Input Nilai Ketiga");
    int n3= Integer.valueOf(c).intValue();
    int rata=(n1+n2+n3)/3;
    String hasil = "";
    hasil += "Nilai Pertama   :" + n1 + "\n";
    hasil += "Nilai Kedua     :" + n2 + "\n";
    hasil += "Nilai Ketiga    :" + n3 + "\n";
    hasil += "Rata-Rata nilai :" + rata + "\n";
    if (rata>=60){
        hasil +="Good :)"+"\n";
    }
    else{
        hasil +=":("+"\n";
    }
    JOptionPane.showMessageDialog(null, hasil);
  }
}


Output :