java动态编译时 报java.lang.ClassNotFoundException

eclipse中java动态编译时出现了不能找到类
我的代码如下

package wmw.run.view;



import java.io.*;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;



/** 

 * @author Every E-mail/MSN:mwgjkf@hotmail.com

 *               QQ:30130942

 * @version 创建时间：Dec 30, 2008 3:34:57 PM 

 * 类说明:

 *

 */

public class RuntimeCode{

	/**编译器*/

	private static com.sun.tools.javac.Main javac=new com.sun.tools.javac.Main();

	

	/**等待用户输入JavaCode,然后编译、执行*/

	public static void main(String[] args) throws Exception{

		String code = "";

		DataInputStream bd = new DataInputStream(System.in);

		byte[] brray= new byte[200];

		int i = bd.read(brray);

		code = new String(brray,0,i);

		run(compile(code));

		System.out.println(code);

	}

	

	/**编译JavaCode,返回临时文件对象*/

	private synchronized static File compile(String code)throws IOException,Exception{

	

		File file;

		

		//在用户当前文件目录创建一个临时代码文件

		file=File.createTempFile("JavaCode",".java",new File(System.getProperty("user.dir")));

		

		//当虚拟机退出时，删除此临时java源文件

		file.deleteOnExit();

		

		//获得文件名和类名字

		String filename=file.getName();

		String classname=getClassName(filename);

		System.out.println(classname);

		//将代码输出到文件

		PrintWriter out=new PrintWriter(new FileOutputStream(file));

		out.write("class "+classname+"{"+"public static void main(String[] args) "+"{");

        out.write(code);

        out.write("}}");

		

		//关闭文件流

		out.flush();

		out.close();

		

		//编译代码文件

		String[] args=new String[]{"-d",System.getProperty("user.dir"),filename};

		

		//返回编译的状态代码

		int status=javac.compile(args);

		

		//处理编译状态

		System.out.println(status);

        return file;

	}

	

	/**执行刚刚编译的类文件*/

	private static synchronized void run(File file){

		//当虚拟机退出时，删除此临时编译的类文件

		//获得文件名和类名字

		String filename = file.getName(); 

		String classname = getClassName(filename);

		new File(file.getParent(),classname+".class").deleteOnExit();

		try {

			// 访问这个类 

			Class cls = Class.forName(classname); 

			//调用main方法 

			Method main = cls.getMethod("main", new Class[] { String[].class }); 

			main.invoke(null, new Object[] { new String[0] }); 

		}catch (SecurityException se) { 

			debug("access to the information is denied:" + se.toString()); 

		}catch (NoSuchMethodException nme) { 

			debug("a matching method is not found or if then name is or : " + nme.toString()); 

		}catch (InvocationTargetException ite) { 

			debug("Exception in main: " + ite.getTargetException()); 

		}catch (Exception e){ 

			debug(e.toString()); 

			e.printStackTrace();

		} 

	}

	

	/**打印调试信息*/

	private static void debug(String msg){

		System.err.println(msg);

	}

	

	/**根据一个java源文件名获得类名*/

	private static String getClassName(String filename){

		return filename.substring(0,filename.length()-5);

	}

}

错误如下
for(int i=0;i<10;i++){System.out.println(i);}
JavaCode423
0java.lang.ClassNotFoundException: JavaCode423

java.lang.ClassNotFoundException: JavaCode423
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at wmw.run.view.RuntimeCode.run(RuntimeCode.java:74)
at wmw.run.view.RuntimeCode.main(RuntimeCode.java:25)
for(int i=0;i<10;i++){System.out.println(i);}



哪位高手知道这是怎么回事
项目中我加入了tools.jar
谁能帮我解决下不胜感激