The JavaMelody platform is current and we have seen some good, and recent, articles on this framework. From the web site: The goal of JavaMelody is to monitor Java or Java EE applications servers in QA and production environments. It is not a tool to simulate requests from users, it is a tool to measure and calculate statistics on real operation of an application depending on the usage of the application by users.

If you’re looking for an end to end J2EE monitoring solution this should be of interest. The Company looks sound and they do sell a commercial licensed version but that said the tracing down to the database layers does seem comprehensive in the open source version documentation. We (the software testing directory) do not see many Web based frameworks in the open source space for J2EE monitoring so this one caught our eye.

Java heap dumps are snap shots of Java heaps at specific times. Java heap areas define objects, arrays, and classes. When the Garbage Collector allocates areas of storage in the heap, an object continues to be live while a reference to it exists somewhere in the active state of the JVM; therefore the object is reachable. When an object ceases to be referenced from the active state, it becomes garbage and can be reclaimed for reuse.

Hyperic is another company that offers two J2EE monitoring solutions, including an open source version. We have not tried this out but the Company is sound and the web based solution (screen shots) look promising. One of the ‘unique’ features mentioned is the ability to discover and monitor all network resources, regardless of location and type.

JConsole monitors Heap memory Usage, Threads (for deadlocks) and controls logging of events. If you are looking to get started with monitoring a J2SE application then this is the place. Other tools provide more specialized analysis (for example heap analysis) but the JConsolce is the general health check perspective.

Given the software testing directory focuses on open source we mainly reference Java related monitoring, as well as the basic LAMP (Linux, Apache, MySql and PHP or Perl) references. That said the Java performance documentation from Sun is the main reference point for all Sun related java performance resources (white papers etc.).

VisualVM is targeted at the developer and System Administartor although this multifaceted tool can be used by the end user (tester) to create more meaningful bug reports. This tool goes deeper (than JConsole) into thread dumps and memory heap dumps. CPU profiling (usage) by application is also provided; the Visual dimension of this application is various screens that quickly identify hot spots in terms of memory or CPU resources being consumed by a given process.

Use the Memory Analyzer to analyze productive heap dumps with hundreds of millions of objects, quickly calculate the retained sizes of objects, see who is preventing the Garbage Collector from collecting objects, run a report to automatically extract leak suspects.