If you assemble a large, shared library into every module that uses it, the result is a huge file that takes too long to register with the server. In addition, several versions of the same class could exist in different class loaders, which is a waste of resources. When Java EE applications and modules use shared framework classes (such as utility classes and libraries), the classes can be put in the path for the common class loader or an application-specific class loader rather than in an application or module. For more information, see Chapter 2, Class Loaders, in Oracle GlassFish Server 3.0.1 Application Development Guide.
According to the Java EE specification, section 18.104.22.168, “Dependencies,” you cannot package utility classes within an individually-deployed EJB module. Instead, you must package the EJB module and utility JAR within an application using the JAR Extension Mechanism Architecture.