Java exception in thread

import java.awt.*;
import java.io.*;
import sun.audio.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.Color.*;
import javax.swing.JFrame.*;
import java.awt.EventQueue.*;

public class EncMain extends JFrame
{
	private JLabel imageIcon;
	private JComboBox box1;
	private JButton button1;
	private JLabel label1;
	private JLabel label2;
	private JTextField field1;


	public EncMain()
	{
		JLabel label1 = new JLabel();
		JLabel label2 = new JLabel();
		JButton button1 = new JButton();
		JTextField text1 = new JTextField();
		JComboBox box1 = new JComboBox();

		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setTitle("Main Menu");
		setBackground(new Color(204, 102, 0));

		label1.setIcon(new ImageIcon ("bible3.gif"));
		label1.setBorder(BorderFactory.createLineBorder(Color.blue));

		label2.setIcon(new ImageIcon ("seed.jpg"));
		label2.setPreferredSize(new Dimension(414,330));

		button1.setBackground( new Color(0, 0, 0));
		button1.setForeground(new Color(255, 0, 0));
		button1.setText("Exit");

		text1.setBackground(new Color(0, 102, 102));
		text1.setFont(new Font("Times New Roman", 1, 24));
		text1.setText("Welcome to Wisdom");

		box1.setModel(new DefaultComboBoxModel(new String[]
		{
			"Gospel", "Raeggae", "Hip-Hop"

		}));
		GroupLayout layout = new GroupLayout(getContentPane());
		getContentPane().setLayout(layout);
		layout.setHorizontalGroup(
			layout.createParallelGroup(GroupLayout.Alignment.LEADING)
			.addGroup(layout.createSequentialGroup()
			.addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)
			.addGroup(layout.createSequentialGroup()
			.addComponent(label2, GroupLayout.PREFERRED_SIZE, 340, GroupLayout.PREFERRED_SIZE)
			.addPreferredGap(LayoutStyle.ComponentPlacement.RELATED, 286, Short.MAX_VALUE)
			.addComponent(label1, GroupLayout.PREFERRED_SIZE, 146, GroupLayout.PREFERRED_SIZE))
			.addGroup(layout.createSequentialGroup()
				.addGap(300, 300, 300)
				.addComponent(button1, GroupLayout.PREFERRED_SIZE, 156, GroupLayout.PREFERRED_SIZE)))
			.addContainerGap())
			.addGroup(layout.createSequentialGroup()
				.addGap(262, 262, 262)
				.addComponent(text1, GroupLayout.PREFERRED_SIZE, 228, GroupLayout.PREFERRED_SIZE)
				.addPreferredGap(LayoutStyle.ComponentPlacement.RELATED, 116, Short.MAX_VALUE)
				.addComponent(box1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
				.addGap(108, 108, 108))

		);

                          pack();
                          setVisible(true);



		layout.setVerticalGroup(
			layout.createParallelGroup(GroupLayout.Alignment.LEADING)
			.addGroup(layout.createSequentialGroup()
			.addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)
			.addGroup(layout.createSequentialGroup()
			.addGap(8, 8, 8)
			.addComponent(field1, GroupLayout.PREFERRED_SIZE, 32, GroupLayout.PREFERRED_SIZE)
			.addPreferredGap(LayoutStyle.ComponentPlacement.RELATED)
			.addComponent(label2, GroupLayout.PREFERRED_SIZE, 275, GroupLayout.PREFERRED_SIZE))
			.addGroup(layout.createSequentialGroup()
			.addGap(16, 16, 16)
			.addComponent(box1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
			.addGap(18, 18, 18)
			.addComponent(label1)))
			.addPreferredGap(LayoutStyle.ComponentPlacement.RELATED, 26, Short.MAX_VALUE)
			.addComponent(button1, GroupLayout.PREFERRED_SIZE, 53, GroupLayout.PREFERRED_SIZE)
			.addContainerGap())

			);
			pack();
			setVisible(true);
		}
		public static void main(String[] args)
		{
			new EncMain();
		}

}