Latest Progress and Trends in Java/EJB Technologies V Sumio Tasaka V Jun Ginbayashi (Manuscript received February 2, 2004) Java is evolving into a full-scale system development technology by the addition of functions such as Applets, object-oriented programming, cross-platform support, internationalization, JavaBeans, Remote Method Invocation (RMI), Java Database Con- nectivity (JDBC), Enterprise JavaBeans (EJB), Java Plug-in, HotSpot Client Virtual Machine (VM), Java Naming and Directory Interface (JNDI), RMI/Internet Inter-ORB Pro- tocol (IIOP), eXtensible Mark-up Language (XML) support, and Java Secure Socket Extension (JSSE). These functions have been added in three specifications: Java 2 Platform, Enterprise Edition (J2EE); Java 2 Platform, Standard Edition (J2SE); and Java 2 Platform, Micro Edition (J2ME). Also, the manner in which these specifications are decided has shifted from decisions made by Sun Microsystems to decisions made by an open community through a process called the Java Community Process (JCP). The main key-phrase of the latest trend in Java/EJB is “Ease of Development,” and J2SE 1.5 (code name “Tiger”) will play a central role in this trend. Prospective enhancements in the Java programming language specifications such as Generics, Enhanced for Loop, Autoboxing/Unboxing, Typesafe Enums, Varargs, Static Import, and Metadata are expected to simplify system development, learning, and mastering. With these new technologies, Java will be used by a wider range of developers and EJB-based development of enterprise systems will become more popular. 1. Introduction the direction of future enhancements in Java/EJB, Since its appearance in 1995, Java technolo- mainly based on the themes that are currently gy (including Enterprise JavaBeans [EJB]) has being discussed in the Java Community Process been evolving with various functions towards a (JCP). In Section 4, the details of the latest ver- technology for full-scale system development. sion (Java 2 Platform, Standard Edition [J2SE] Frequent enhancements with these functions have 1.5), whose outline has just become clear, are in- led to a wider Java application area. However, troduced. Finally, Section 5 concludes with a brief these enhancements have raised application look at the future of Java/EJB. developers’ feelings of insecurity about the stabil- ity of Java and forced them to spend more time 2. History and current status of learning and mastering Java. Java This paper aims to eliminate unnecessary Java was introduced by Sun Microsystems anxiety among developers by looking back on the in 1995 together with a browser, HotJava. Then, history of Java/EJB technology and clearly show- Java gained public attention in the form of Ap- ing its future trend. plets, which are programs running on a browser, First, in Section 2, the history so far of Java/ and was later expanded to include, for example, EJB technology is summarized. Section 3 shows server-side applications and mobile appliances. FUJITSU Sci. Tech. J., 40,1,p.85-93(June 2004) 85 S. Tasaka et al.: Latest Progress and Trends in Java/EJB Technologies The major version upgrades of Java are name “Java 2.” In JDK 1.2, the following func- shown in Table 1. tions were added: The major enhancement points of each ver- • Java Foundation Classes (JFC) sion are given below. • Input Method Framework (IMF) 1) Version 1.0 •Common Object Request Broker Architecture Java Development Kit (JDK) 1.0 was an- (CORBA) support nounced as the first release of Java with the • EJB following features: • Java Plug-ins • Object orientation After the release of Java 2, EJB made its • Cross-platform support appearance and more enterprise systems were • Network compatibility developed using the server-side version of Java. Because it was a C++-like language, and also It would appear that, at first, Java was expected because of its simple and pure language specifi- to be effective for solving the shortage of client- cations, Java was quickly and warmly accepted side applications on platforms other than Windows by developers, which is unusual for a new lan- (as implied by the catch phrase, “write once, run guage. However, it did not have sufficient anywhere”). However, server-side Java became functions for system development. Also, it was popular in those days because of the expansion of difficult to use Java in a Japanese environment, the Internet. because internationalization was not supported. 4) Version 1.3 2) Version 1.1 From JDK 1.3, Java and its related functions Approximately one year later, JDK 1.1 was were reorganized into the following three editions announced. The following functions were added based on the target system environment: Java 2 in JDK 1.1: Platform, Enterprise Edition (J2EE);1) Java 2 Plat- • Internationalization form, Standard Edition (J2SE);2) and Java 2 • JavaBeans Platform, Micro Edition (J2ME). • Remote Method Invocation (RMI) J2SE 1.3 had the following additional func- •A new event model tions: • Java Database Connectivity (JDBC) • HotSpot Client Virtual Machine (VM) Java did not have enough functions to sup- • Java Naming and Directory Interface (JNDI) port system development until functions such as •RMI/Internet Inter-ORB Protocol (IIOP) JavaBeans and JDBC were provided in this • Security enhancements version. After the release of version 1.3, the way in 3) Version 1.2 which Java will be applied to enterprise systems From JDK 1.2, Java was given the new brand became clear with the editions based on target Table 1 Major version upgrades of Java. Major Java upgrades Version Name Release date May 1995 Java (announced) January 1996 1.0 JDK 1.0 February 1997 1.1 JDK 1.1 December 1998 1.2 Java 2 (JDK 1.2) July 2000 1.3 Java 2 (J2SE 1.3, J2EE 1.2, J2ME) February 2002 1.4 Java 2 (J2SE 1.4, J2EE 1.3, J2ME) 86 FUJITSU Sci. Tech. J., 40,1,(June 2004) S. Tasaka et al.: Latest Progress and Trends in Java/EJB Technologies Client Server Business presentation presentation logic EIS tier tier tier tier Applet Servlet EJB DB HTML JSP DB Servlet EJB Web browser container container DBMS Figure 1 J2EE application model and components. platforms. In particular, Java application to en- Business logic tier terprise systems became more popular after EJB 2.0 and JavaServer Pages (JSP) were announced in J2EE. Figure 1 shows the application model Business Business service model and components supported by J2EE. To make it component component easier to build enterprise systems through com- ponent-based development, several detailed EJB container application models based on EJB have been ad- vocated by companies and consortiums such as Figure 2 EJB-based application model of Component Consortium 3) the Component Consortium for EJB, which has for EJB. been established in Japan. Figure 2 shows the EJB-based application model of the Component functions. Since version 1.4, however, the specifi- Consortium for EJB. At the same time, because cations have been decided in a more open manner. of J2ME, the application area of Java expanded Now, new specifications and improvements of ex- to include mobile appliances, which led to the cur- isting specifications are made based on Java rent widespread use of Java in mobile-phone Specification Requests (JSRs) submitted by the applications. Java community to a process called the Java Com- Among the enhancements in version 1.3, the munity Process (JCP).4) following functions added to EJB in EJB 2.0 are When a JSR is submitted to the JCP, the important because they can be used to design and member companies of the JCP discuss whether it implement coarse-grained entities and make data- should be implemented. If they decide it should base access more efficient, which are both necessary be implemented, an expert group is established tasks when developing enterprise systems: to decide the final specifications for the JSR. Only •A new architecture for container-managed member companies of the JCP can submit a JSR, persistence (CMP 2.0) but submitted JSRs are made public on the JCP’s • Support for the management of relationships Web site so the JCP can receive a wider range of among entity beans opinion. • Query syntax for select methods for entity J2SE 1.4 was the first version whose specifi- beans (EJB-QL) cations were discussed and determined by the JCP. •Message-driven beans The following functions were added: 5) Version 1.4 •XML support Until version 1.3, Sun Microsystems decid- •Java Web Start ed the specifications of Java and its related •A new I/O FUJITSU Sci. Tech. J., 40,1,(June 2004) 87 S. Tasaka et al.: Latest Progress and Trends in Java/EJB Technologies •A logging API to learn and there are relatively few high-level • Assertion developers. For this reason, Java is not so suc- • Java Secure Socket Extension (JSSE) cessful in the area of section-wise application, In this way, the specifications of Java are now where Basic and C# are used. On the other hand, discussed and evolved within an open community. Java is successful in the area of mobile applianc- es and enterprise systems. 3. Future enhancements of Java As a result, for the next version of Java, ease A roadmap for future enhancements of Java of development rather than function enhancement has been released.5) The roadmap is shown in will be the priority issue. This could be the larg- Table 2. est change of policy since Java was born. As described in Section 2, the application The next version of Java will be J2SE 1.5 area of Java has become wider and Java technol- (code name “Tiger”). For J2SE 1.5, the following ogy is becoming more popular. J2ME has been five themes will be considered: adopted in mobile appliances such as mobile 1) Quality: compatibility will be extremely im- phones.