JFinal调试时自动加载新文件报错

@JFinal

在Eclipse中，直接用JFinal调用Jetty调试，启动的时候是正常的，但是修改java文件后，重新加载会报：

2014-07-03 16:50:26.648:WARN:oejuc.AbstractLifeCycle:FAILED jfinal: java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory

java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
 at net.sf.ehcache.CacheManager.<clinit>(CacheManager.java:125)
 at com.jfinal.plugin.ehcache.EhCachePlugin.createCacheManager(EhCachePlugin.java:90)
 at com.jfinal.plugin.ehcache.EhCachePlugin.start(EhCachePlugin.java:61)
 at com.jfinal.core.Config.startPlugins(Config.java:85)
 at com.jfinal.core.Config.configJFinal(Config.java:48)
 at com.jfinal.core.JFinal.init(JFinal.java:67)
 at com.jfinal.core.JFinalFilter.init(JFinalFilter.java:49)
 at org.eclipse.jetty.servlet.FilterHolder.doStart(FilterHolder.java:119)
 at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
 at org.eclipse.jetty.servlet.ServletHandler.initialize(ServletHandler.java:724)
 at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:265)
 at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1250)
 at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:706)
 at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:492)
 at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
 at com.jfinal.server.JettyServer$1.onChange(JettyServer.java:106)
 at com.jfinal.server.Scanner.compare(Scanner.java:87)
 at com.jfinal.server.Scanner.working(Scanner.java:56)
 at com.jfinal.server.Scanner.access$0(Scanner.java:54)
 at com.jfinal.server.Scanner$1.run(Scanner.java:93)
 at java.util.TimerThread.mainLoop(Unknown Source)
 at java.util.TimerThread.run(Unknown Source)