You should ask on the JBoss AS list what they use it for. But I assume for anything jaxb related and that would probably be for a lot of apps using any of the projects using jaxb (need to verify) So my guess is that we can't remove this jar, and doing so would also only be removing the current problem, not solving the underlying issue. What should be done is: 1) make sure that the eclipse issue snjezana reported and the patch get's considered so it might just go away in an update. 2) Make AS team aware of the 1.0 folder issue and figure out why it is there in the first place. What is inside that file anyway ? (I'll do this - Alexey L. who works on jaxb is here in Neuchatel) 3) We should fix the old age issue in JBIDE that talks about having a preference on the runtimes what jar's they should actually expose/pickup! /max