I am attempting to move a number of war applications to an ear file that can be deployed on any standard J2EE server. I am having difficulty however dealing with tag libraries on JBoss. In order to start the conversion I have placed one of our war files into an ear file and have moved all of the common libraries (those shared by multiple wars) into the ear file. I have modified the /META-INF/MANIFEST.MF files within the war file to contain the classpath entry that includes the required shared jar files. Also, the application.xml contains a web module that points to the included war. It appears that the war is loaded and the external libraries are being loaded, but when a JSP includes the JSTL taglib the server throws an error that ?The absolute uri: http://java.sun.com/jsp/jstl/core cannot be resolved in either web.xml or the jar files deployed with this application.? I have the ear file organized as follows: MYAPP.EAR | | | |-- META-INF/ | | |-- application.xml | | `-- MANIFEST.MF | | | |-- schoolDays.war | | |-- META-INF/ | | | `-- MANIFEST.MF | | `-- WEB-INF | | `-- web.xml | | | |-- spring.jar | |-- jstl.jar | `-- standard.jar Does anyone know how to resolve this issue? I know that I can copy the standard.jar and jstl.jar files to the WEB-INF/lib directory of the war, but this will require that those jars be duplicated in each war and I would like to avoid the duplication of utility/library jar files. Likewise, I would like to be able to avoid placing libraries in the server classpath. Is it possible to have JBoss (4.0.5GA) load tag libraries that are located in jar files contained in the ear itself? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4045092#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...