求帮忙看一段java代码，很短的

Question

import java.util.*;
public class Student implements Comparable {
int score=0;
String name;
Student(int score,String name){
this.name=name;
this.score=score;
}
public int compareTo(Object b){
Student st=(Student)b;
return(this.score-st.score);
}
}

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.*;
import java.util.*;
public class sum {
public static void main(String[] str){

TreeSet<Student> mytree=new TreeSet<Student>();
int i=0;
final Student[] stu=new Student[20];

final JFrame frame=new JFrame();
frame.setSize(400, 500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel=new JPanel();
JPanel panel1=new JPanel();
final JTextField input1=new JTextField(5);
final JTextField input2=new JTextField(5);
final JTextArea jtx=new JTextArea(300,400);    
jtx.setVisible(true);
JLabel label= new JLabel("名字");
JLabel label1=new JLabel("分数");
JButton button=new JButton("显示");

BorderLayout layout=new BorderLayout(10,10);
FlowLayout gl=new FlowLayout();
panel.setLayout(gl);
panel1.setLayout(layout);

panel.add(label);     panel.add(input1);
panel.add(label1);  panel.add(input2);
panel.add(button);

panel1.add(panel,"North");
panel1.add(jtx,"South");
frame.add(panel1,BorderLayout.NORTH);
frame.setVisible(true);

button.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent e){
        String str1=input1.getText().trim();
        String str2=input2.getText().trim();
         int num = Integer.parseInt(str2); 

        stu[i]=(num,str1);
        mytree.add(stu[i]);
        Iterator<Student> te=mytree.iterator();
        mytree.add(stu[i]);
        Iterator<Student> te=mytree.iterator();
        jtx.setText(jtx.getText()+"名字"+str1+"分数"+num+"\n");;

        while(te.hasNext()){
            Student stu0=te.next();
            jtx.setText(""+stu0.name+" "+stu0.score);
        }

}
});
}
}

Answer 1

看什么？出错了？直接上错误提示啊