If you download and install Java 1.6 then the updated version of Jconsole can be run against Sakai on a Java 1.5 platform. The newest version can detect thread deadlocking and has a pluggable structure.
For example to run Jconsole with the a pseudo top command tab on Ubuntu then try something similar to:
/usr/lib/jvm/java-6-sun-1.6.0.00/bin/jconsole -pluginpath Jtop.jar