S A M P L E   P R O J E C T  

Call the compiler etc. by hand on the command line 

Use a script file containing the list of commands to build your system 

Use the  make  tool 

Use the  ant  tool 

For Java projects the time you save increased down the list. The first item is not even 

suitable for a simple test because you will compile and run several times until it is working 

you will spend too much time anyhow. The script file will always recompile all source files 

etc. and therefore repetitive use will slow you down. The good old  make  tool is suitable 

when the most of your components are not Java or you have to use it because of some 

company policies. The drawback is that it calls the Java compiler for each file and therefore 

it is pretty slow especially when you recreate the project complete.  make  is also pretty 

difficult to us. 

All this was the reason for David Duncan Davidson (see Jakarta) to write a simple build tool 

based on XML. It was used to build Jakarta's Tomcat web server and became famous as 

 ant . Currently it is one of or the best build tool available. After spending some time to 

learn it you will never build a project without it (see Appendix B). 

 ant  provides many tasks to help you (compiling, archiving, copy with filtering, run 

JavaDoc, run other programs etc.) but it also allows you to create your own tasks which we 

will see later with XDoclet. On of the weaknesses is that you have difficulty to apply 

conditional compiling but maybe this will be added in the future. 

For now we want to go with  ant  because it is sexy, Java based, open source and you can 

use it for free. Please not that JBoss does not use  ant  directly but through  buildmagic  

supporting builds of multiple projects within the JBoss project. 

Enterprise Java Beans and J2EE Resources 

In J2EE Enterprise JavaBeans (EJBs) and the J2EE Resources is the core of any type of 

applications. The EJBs represents either business objects and their logic or a more advanced 

persistence data object. The J2EE Resources enable EJBs or other components like Servlets 

to access persistent data stores, connection to other (sometimes legacy) systems or 

communicate with others. 

The EJBs are integrated in a mostly vendor neutral set of APIs like JMS, JAAS, JavaMail, 

JCA etc. and their implementation represents the J2EE resources. This means that an EJB 

can be coded in a vendor neutral way to run on different J2EE servers and J2EE resource 

implementation. 

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