linux下tomcat6启动出现日志异常

用命令
 ps -ef|grep tomcat

查看没有tomcat进程。

查看tomcat日志信息，出现了下面的错误：

WARNING: error instantiating 'org.apache.juli.ClassLoaderLogManager' referenced by java.util.logging.manager, class not found
java.lang.ClassNotFoundException: org.apache.juli.ClassLoaderLogManager not found
   >>No stacktrace available>>
WARNING: error instantiating '1catalina.org.apache.juli.FileHandler,' referenced by handlers, class not found
java.lang.ClassNotFoundException: 1catalina.org.apache.juli.FileHandler,
   >>No stacktrace available>>
Exception during runtime initialization
java.lang.ExceptionInInitializerError
   >>No stacktrace available>>
Caused by: java.lang.NullPointerException
   >>No stacktrace available>>

最终解决办法：
用命令设置JAVA_HOME环境变量