Add Object Cache Monitoring Using JMX and Aspects

ike many companies, my company uses an object cache to store frequently accessed data in memory so the server doesn't have to access the back-end database every time it handles a request for the same data. Caching provides advantages such as application performance improvement, scalability and minimizes the overhead required to acquire and release the objects.

In a recent project we needed to view and monitor the cache details (using a Web console) to study the data access trends for objects stored in the cache and determine which objects were better used by storing them in the cache instead of directly going to backend data store. We wanted to use the Java Management Extensions (JMX) technology for this requirement, but didn't want to change any existing application code because we weren't sure how much overhead the monitoring code would add. We decided to use Aspect Oriented Programming (AOP) techniques to dynamically introduce JMX code into existing Java classes and get the cache statistics that way. That way, if the monitoring overhead turned out to require too much overhead, we could easily unweave the JMX code from the application code, returning it to the exact state it was in prior to introducing the monitoring logic.