[Update] Monitoring tomcat instances

Here are some OSS projects to monitor your tomcat instances (f.e. memory-/cpu-usage, sessions, mbeans)

• http://code.google.com/p/psi-probe/ (psi-probe – fork of lambda probe)
• http://www.lambdaprobe.org/ (lambda probe, project seems to be dead)
• http://code.google.com/p/javamelody/(javamelody)

Off course you can also monitor your tomcat via VisualVM (http://visualvm.java.net/ or included in JDK6)

Update: Or use JRDS http://jrds.fr/

maven-surefire-plugin only uses 67MB of heap?

Today i  had to do some merging of artifacts (code and pom.xml). Then i wondered, why the tests didn’t run properly.

“java.lang.OutOfMemoryError: Java heap space” was the reason. But why? I didn’t change the tests and i carefully merged the configuration. So i connected VisualVM to the surefire process and saw that only ca. 67MB max heap were available. I reviewed my MAVEN_OPTS, but my settings didn’t apply…

The culprit is a bug. See http://jira.codehaus.org/browse/SUREFIRE-501.

The workaround is to place your max heap configuration in the configuration section of the plugin. As seen in the linked bug issue:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-surefire-plugin</artifactId>
  <configuration>
    <!-- http://jira.codehaus.org/browse/SUREFIRE-501 -->
    <argLine>-Xmx256m</argLine>
  </configuration>
</plugin>