When trying to run JBoss 3.2.2.RC4 with JDK 1.4.2_01 I'm getting the warning:
"JSP compilation requires $JAVA_HOME/lib/tools.jar on your JBOSS_CLASSPATH"
at startup.
JSP compilation is impossible after this.

I checked the source and saw the following check:
findResourceInJar("com/sun/tools/javac/v8/resources/javac.properties")

In the JDK 1.4.2_01 there is no such file.
In former versions (JDK 1.4.1 and 1.3.1) this file exist.

I don't know if this is a feature or bug from JDK.
But perhaps it would be better to test other file for checking tools.jar.