Unable to compile class for JSP找不出错误
显示是
ClassNotFoundException: org.apache.jsp.BBS.WebRoot.article_jsp
Unable to compile class for JSP:  
的错误  可是就是不知道哪错了  找不出来!!
<%@ page pageEncoding="Gb18030"%>
<%@ page import="java.sql.*,  org.hjj.bbs.*, java.util.*"%>
<%!
private void tree(List<Article> articles , Connection conn , int id , int grade){
  	String sql = "select * from article where pid =" + id;
  	Statement stmt = DB.createStmt(conn);
  	ResultSet rs = DB.executeQuery(stmt , sql);
  	try{
  	while(rs.next()){
  		Article a = new Article();
  		a.initFromRs(rs);
  		a.setGrade(grade);
		articles.add(a);
		if(!a.isLeaf()){
			tree(articles , conn , a.getId() , grade+1);
		}
  	}
  	}catch(
SQLException e){
  		e.printStackTrace();
     }
       finally {
		 DB.close(rs);
		 DB.close(stmt);
  	}  
}
%>
<%
List<Article> articles = new ArrayList<Article>();
Connection conn = DB.getConn();
tree(articles,conn,0,0);
DB.close(conn);
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
	<head>
		<title>论坛: Java语言*初级版</title>
		<meta http-equiv="content-type" content="text/html; charset=UTF-8">
		<link rel="stylesheet" type="text/css" href="images/style.css">
	</head>
	<body>
		<table border="0" cellpadding="0" cellspacing="0" width="100%">
			<tbody>
				<tr>
					<td width="1%">
						<a href="http://bbs.chinajavaworld.com/index.jspa">;ti<img
								src="images/header-left.gif" alt="JAVA中文世界论坛|JAVA开发者论坛"
								border="0" height="38" width="199"> </a>
					</td>
					<td width="98%">
						<img src="images/header-stretch.gif" alt="" border="0" height="38"
							width="100%">
					</td>
					<td width="1%">
						<img src="images/header-right.gif" alt="" border="0" height="38"
							width="5">
					</td>
				</tr>
			</tbody>
		</table>
		<br>
		<p class="jive-page-title">
			论坛: Java语言*初级版
		</p>
		<p class="jive-description">
			 
		</p>
		<link rel="alternate" type="application/rss+xml" title="RSS"
			href="http://bbs.chinajavaworld.com/rss/rssmessages.jspa?forumID=20">
		<script language="JavaScript" type="text/javascript"
			src="images/common.js"></script>
		<div id="jive-forumpage">
			<div class="jive-buttons">
				<table summary="Buttons" border="0" cellpadding="0" cellspacing="0">
					<tbody>
						<tr>
							<td class="jive-icon">
								<a
									href="http://bbs.chinajavaworld.com/post%21default.jspa?forumID=20"><img
										src="images/post-16x16.gif" alt="发表新主题" border="0" height="16"