The Java Application Monitor (JAMon) is a free, simple, high performance, thread safe, Java API that allows developers to easily monitor production applications.
1) It contains the ability to monitor JDBC/SQL, web page requests, ejb's, log4j, interfaces and more.
2) It tracks aggregate stats for each sql statement, page request etc. and also lets you look at this information and more via the JAMon war.
3) You can also access JAMon statistics via the api