Could not load com.mysql.jdbc.SQLError.

信息: Illegal access: this web application instance has been stopped already. Could not load com.mysql.jdbc.SQLError. The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
java.lang.IllegalStateException
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1246)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1206)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3134)
at com.mysql.jdbc.MysqlIO.quit(MysqlIO.java:1616)
at com.mysql.jdbc.ConnectionImpl.realClose(ConnectionImpl.java:4223)
at com.mysql.jdbc.ConnectionImpl.cleanup(ConnectionImpl.java:1257)
at com.mysql.jdbc.ConnectionImpl.finalize(ConnectionImpl.java:2663)
at java.lang.ref.Finalizer.invokeFinalizeMethod(Native Method)
at java.lang.ref.Finalizer.runFinalizer(Finalizer.java:83)
at java.lang.ref.Finalizer.access$100(Finalizer.java:14)
at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:160)
编网站是老碰到的异常
struts+tomcat+netbeans+ajax+mysql
网站能正常工作，包都导对的

相关了解……