The following exception is thrown when generating entities from database using seam-gen. This issue is related to JBPAPP-6347. Nevertheless, renaming the ecj.jar to core.jar does not help, since the former core.jar contains much more classes (including org/eclipse/jdt/core/ToolFactory) while the ecj.jar does not.

BUILD FAILED
[testng] w:\workspace\seam-gen-eap5-win\jboss-eap-5.1\seam\seam-gen\build.xml:1390: java.lang.NoClassDefFoundError: org/eclipse/jdt/core/ToolFactory