Testing Conformance of EJB 3 Enterprise Application Servers

摘要

Enterprise JavaBeans (EJB) is a component technology used for enterprise application development. EJB is currently being implemented by such application servers as GlassFish, OpenEJB, JBoss, WebLogic and Apache Geronimo. Through the entire history EJB claimed its adherence to the "write once, run anywhere" philosophy of Java suggesting that an application developed for and deployed on one application server should be easily portable to a different application server. Therefore, one could have expected different application servers to adhere to the EJB specification. Adherence to this and related Java EE specifications is subject of the "Java EE 6 Full Profile" compatibility testing carried by Oracle. However, anecdotal evidence of discrepancies between the specification and certified implementations such as GlassFish, has been reported in the literature. In this paper we present an approach allowing one to go beyond the level of anecdotal knowledge and test requirements for EJB application servers with focus on portability. We apply the approach developed to test how well two popular "Java EE 6 Full Profile"-compatible EJB application servers, GlassFish and JBoss, conform to the requirements in the EJB specification. The results are alarming: both application servers failed on a number of tests, violating the specification. Moreover, in GlassFish conformance to a requirement varies depending on whether a local or a remote application is used. Lack of conformance to the EJB specification compromises the portability of the EJB applications, deviates from the portability philosophy of Java, leads to unexpected behaviour, and hinders the learning process of novice EJB developers.