[HELP]yg jago java msk please

[Guesuper]

gan program ane eror.... nah ane bingung n erorny dmn,

pas ane jalanin erorny s cm 1,di line 6

langsung aja dagh n codingannya

<div style="margin:20px; margin-top:5px">
Spoiler for kodingannya gan:


<div class="alt2" style="margin: 0px; padding: 6px; border: 1px inset;">
<div style="display: none;">


import java.awt.*;

import java.awt.event.*;

import javax.swing.*;



class comboBox implements ActionListener

{

public JLabel nama,tgl,labeltgl,labelbulan,labeltahun;

public JTextField kode,info;

public JComboBox tanggal,bulan,tahun;

public JButton proses;



//combo box

public comboBox()

{

//label nama

String s1 = "Kode Barang;";

nama = new JLabel(s1);

nama.setLocation(10, 10);

nama.setSize(nama.getPreferredSize());



//text nama

kode = new JTextField(99);

kode.setLocation(10, 30);

kode.setSize(nama.getPreferredSize());



//label tanggal

String s2 = "Tanggal;";

tgl = new JLabel(s2);

tgl.setLocation(10, 55);

tgl.setSize(tgl.getPreferredSize());



labeltgl = new JLabel("Tanggal");

labeltgl.setLocation(35, 75);

labeltgl.setSize(tgl.getPreferredSize());



//combo box tanggal

tanggal = new JComboBox();

tanggal.setLocation(35, 93);

tanggal.setSize(tgl.getPreferredSize());

for(int i=0;i