java中提示这样的错误 java.awt.AWTError: BoxLayout can't be shared

/*
* tiger class
*
*/

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;

import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

//import LoginQQCompany.BottomPane;
import LoginQQCompany.BottomPane;

import LoginQQCompany.TopPane;

public class Tiger extends JFrame{

/**
* @param args
*/
private static JPanel box_Y_L=new JPanel(new BoxLayout(null,BoxLayout.Y_AXIS));

private static JPanel box_Y_R=new JPanel(new BoxLayout(null,BoxLayout.Y_AXIS));

private static JPanel panel=new JPanel();
/**
* 服务器地址，端口号
*/
private static JLabel serverLabel=new JLabel("服务器地址：");
private static JLabel portLabel=new JLabel("端 口 号：");
private static JTextField serverText=new JTextField(20);
private static JTextField portText=new JTextField(20);
private static JLabel netsetLabel=new JLabel("网络设置");
private static JPanel panel1=new JPanel();
public static JPanel BottomPane() {
panel1.add(netsetLabel,BorderLayout.NORTH);

box_Y_L.add(serverLabel);
box_Y_L.add(portLabel);
box_Y_R.add(serverText);
box_Y_R.add(portText);

panel.setLayout(new BoxLayout(null,BoxLayout.X_AXIS));//盒式布局 组件横向排列
panel.setBackground(Color.white);
panel.setPreferredSize(new Dimension(Short.MAX_VALUE,30));//设置首选大小
panel.setMaximumSize(new Dimension(Short.MAX_VALUE,30));//设置最大大小

panel.add(box_Y_L);panel.add(box_Y_R);
panel1.add(panel,BorderLayout.CENTER);
return panel1;
}
// TODO Auto-generated constructor stub
public static void main(String[] args) {

// TODO Auto-generated method stub

Console console=new Console();
Console.run(BottomPane(), 300, 300);
}
}