I don't have Solaris so I am just venturing a guess. Considering that Sun develops Solaris and Java, I would guess that SUNWj5rt is an official JRE (Java Runtime Environment), that is, the say JRE you would download from the Sun Java web site. This is in contrast to Linux distributions which come a pseudo-JVM that is not fit to run JBossAS (in which case you need the JDK from Sun). The error your got is because JBossAS really prefers to run with a JDK (which includes the compilers and tools). In ancient times (say 3 or 4 years ago), web containers (such as Tomcat) required a JDK to compile the JSPs found in web applications, and the check for a JDK is still in the startup scripts. You should not have any problem using the JRE unless you are using, in one of your applications, a Java library that needs it. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4121353#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...