Paul René Jørgensen

Did you ever want to be the Big Brother of the Java Virtual Machine? Being able to do non intrusive monitoring of method calls without access to the source code, performing this in a production environment without a noticeable performance hit?

Do you want to know who is doing what to whom, that is, who invokes what method in context of which principal? Making certain that memory consumption is dynamically adjusted to avoid out of memory situations? Would you also like to use it in your legacy applications running pre Java 5 as well as utilize the new Java agent interface of the newer JVMs?

You know you have to collect vast amount of data and process it effectively and in real time. Finally you figure out that the amount of data exceeds the capabilities of a traditional data model and you decide that the only solution is a dimensional data model, using MDX for multi dimensional analysis.

There are numerous tools available for profiling and measuring your Java programs. However these tools are either: a) aimed at profiling or measuring your code in a development environment; b) expensive; c) not open source; d) requires a Ph.D. in debugging and profiling e) any combination of the above

Usemon attempts to alleviate this by providing an open source tool which is easy to use, collects data from environments based upon Java 1.4 through 6, has a flexible dimensional data model stored in a SQL database and attempts to be non-intrusive.

Usemon hooks into the Java virtual machine through a modified class loader on older JVMs or via the Java Agent Interface from version 5 and up. It automatically monitors Java EE components (EJBs, Servlets, MDBs, Queues, SQL Statements, etc), but can be configured to inspect any class in your JVM. Data is multicasted from agents to one or more collectors and stored in the DBMS of your choice. Usemon comes with a complete configuration for MySQL.

The overhead of running Usemon is negligible and thus you may collect run-time statistics around the clock all year, which is rather fascinating, given that you have enough disk space.

Usemon was developed for large Java EE environments at Telenor, which is one of the worlds largest telco to fulfill these requirements. You may utilize it in any environment in which you have control over the Java Virtual Machine start up parameters. For example Java EE applications, Spring based Web applications or simply your own home grown web application packaged in a .war file.

You may download or check out the source code at http://usemon.org