Overview

Lambda Probe (formerly Tomcat Probe) is a self sufficient web application, which helps to visualize various parameters of Apache Tomcat instance in real time. Lambda Probe is designed to work specifically with Tomcat so it is able to access far more information that is normally available to JMX agents. Here is a list of features available through Lambda Probe:

New! Comprehensive JVM memory usage monitor.
JBoss compatibility
Display of deployed applications, their status, session count, session object count, context object count, datasource usage etc.
Start, stop, restart, deploy and updeploy of applications
Ability to view deployed JSP files
Ability to compile all or selected JSP files at any time.
Ability to pre-compile JSP files on application deployment.
New! Ability to view auto-generated JSP servlets
Display of list of sessions for a particular application
Display of session attributes and their values for a particular application. Ability to remove session attributes.
Ability to view application context attributes and their values.
Ability to expire selected sessions
Graphical display of datasource details including maximum number of connections, number of busy connections and configuration details
New! Ability to group datasource properties by URL to help visualizing impact on the databases
Ability to reset data sources in case of applications leaking connection
Display of system information including System.properties, memory usage bar and OS details
Display of JK connector status including the list of requests pending execution
Real-time connector usage charts and statistics.
Real-time cluster monitoring and clulster traffic charts
New! Real time OS memory usage, swap usage and CPU utilisation monitoring
Ability to show information about log files and download selected files
Ability to tail log files in real time from a browser.
Ability to interrupt execution of "hang" requests without server restart
New! Ability to restart Tomcat/JVM via Java Serview Wrapper.
Availability "Quick check"
Support for DBCP, C3P0 and Oracle datasources
Support for Tomcat 5.0.x and 5.5.x
Support for Java 1.4 and Java 1.5

In addition to a healthy set of useful features Lambda Probe is an admittedly "nice" web application. And to prove (or disprove) that we have screenshot section, which we would recommend visiting before making your mind up ;)

To see Lambda Probe in action please visit LIVE DEMO at http://demo.lambdaprobe.org site. (login demo/demo)

Availability "Quick check"

Using this feature you can almost definitively monitor Apache Tomcat availability. "Quick check" does the following:

Scans all available datasources and generates maximum usage score
Allocates 1MB of memory into byte array
Creates and then deletes 10 files in temp directory

The check fails if either of the following is true

At least one of the declared datasources is 100% used
Memory allocation test generated OutOfMemory exception
File creation test encountered an IOException

Lambda Probe also has XML version of "Quick check" for automated aplication monitoring tools.