eclipse中改变java文件里面的代码,tomcat服务器自动编译报错

log4j:ERROR LogMananger.repositorySelector was null likely due to error in class reloading, using NOPLoggerRepository.
Exception in thread "Timer-1" java.lang.NullPointerException
at com.mchange.v2.log.log4j.Log4jMLog$Log4jMLogger.isLoggable(Log4jMLog.java:257)
at com.mchange.v2.resourcepool.BasicResourcePool$CullTask.run(BasicResourcePool.java:1934)
at java.util.TimerThread.mainLoop(Timer.java:512)
at java.util.TimerThread.run(Timer.java:462)
上网查了
(log4j:ERROR LogMananger.repositorySelector was null likely due to error in class reloading, using NOPLoggerRepository.
·原因：在tomcat的"conf/catalina.properties“文件中末尾追加一条:
org.apache.catalina.loader.WebappClassLoader.ENABLE_CLEAR_REFERENCES=false)
照着改了以后没啥用
1.eclipse导入一个项目,部署到tomcat服务器(),正常启动..没任何错误.
2.任意修改一个java类,比如换行之类的修改,然后保存.
3.这时tomcat会自动将修改的内容同步
4.同步失败,报上面的错误.
5.可能描述的不是很清楚,但是有经验的我相信你看一眼就懂.