请高手帮忙加下java代码注释（4）

import java.sql.*;
import java.util.*;
import java.io.*;

public class bulletin_intro
{
public String bulletin_title;//定义字符串变量bulletin_title

public Collection col=new ArrayList();//建类Collection的对象

public Connection con;

public Collection b_intro() throws Exception{

try{
Statement statement=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
String sql="select * from bulletin_info where bulletin_title='"+bulletin_title+"'";
ResultSet r=statement.executeQuery(sql);

while(r.next())
{
bulletin bul=new bulletin();
bul.setBulletin_title(r.getString(1));//设标题
bul.setBulletin_context(r.getString(2));//设内容
bul.setBulletin_time(r.getString(3));//设时间
col.add(bul);//增加
}
}catch(SQLException ee)//载取异常
{}
return col;
}
}