java小小问题??懂java的人快进!!!

来源：百度知道 编辑：UC知道 时间：2024/06/01 02:17:07
当我编译时,出现了1个错误,在第6行,提示说<<方法声明无效；需要返回类型>>,很郁闷,怎么会错呢,应该怎样改使下面的程序能够通过编译???知道帮帮忙谢谢了!!!
1: import javax.swing.*;
2:
3: public class ChooseTeam extends JFrame {
4: JComboBox monthBox=new JComboBox();
5: JComboBox yearBox=new JComboBox();
6: public Expiration(){
7: super("Expiration Date");
8 setSize(220,90);
9 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel pane=new JPanel("Expiration Date:");
pane.add(exp);
for (int i=1;i<13;i++)
monthBox.addItem(""+i);
for(int i=2000;i<2010;i++)
yearBox.addItem(""+i);
pane.add(monthBox);
pane.add(yearBox);
setContentPane(pane);
show();
}
public static void main (String[] args) {
Expiration ct=new Expiration();
}

}
1楼方法不行的错误越来越多了

好啦 你直接运行看看是不是你要的结果

package com.qhit;

import javax.swing.*;

public class ChooseTeam extends JFrame {
JComboBox monthBox = new JComboBox();

JComboBox yearBox = new JComboBox();

public void Expiration() {
// super("Expiration Date");
setSize(220, 90);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JPanel pane = new JPanel();

pane.add(yearBox);
pane.add(monthBox);
for (int i = 1; i < 13; i++)
monthBox.addItem("" + i);
for (int i = 2000; i < 2010; i++)
yearBox.addItem("" + i);
pane.add(monthBox);
pane.add(yearBox);
setContentPane(pane);
show();
}

public static void main(String[] args) {

ChooseTeam ct = new ChooseTeam();
ct.Expiration();
}

}

package chzhsh;

import javax.swing.*;

public cla