tomcat 6.0.24 Exception: Could not load com.mysql.jdbc.SQLError

Question

My tomcat 5 server running on centos frequently (several times / day) produces the following error:

Apr 7, 2011 11:02:30 PM org.apache.catalina.loader.WebappClas         


        

Answer 1

Apart from using only one version of jar (which the other users have suggested), please check the following as well:

1. Make sure that when you are done with the database connection, close the connection with close() call.
2. Errors like this might occur when you open number of connections and do not explicitly close them.
3. In these situations, many a times, the database actually closes the idle connections but the object representing that connection on application side is still not closed.
4. What happens is, these open connection objects are lurking and when the the finalizer runs (evident from the stack trace) and tries to close the connection, you get IllegalStateException as this connection object is not associated with any database connections.