A P P E N D I X   B  

Appendix 

B 

16. Appendix 

B 

Introducation to ANT Build System 

Before the days of ANT therefore was only  make  available to build your application with 

dependencies to avoid recompilation every time you needed a new build. But  make  is hard 

to write and maintain, is most of the time platform dependent and does not perform well in 

Java because  make  calls the Java compiler for each file instead all at once. 

So on a flight David Duncanson (father of Tomcat) was tired of all this hassle and decided to 

write a Java based build tool to ease the development of Tomcat. As soon as Tomcat was put 

on the CVS repository of 

http://jakarta.apache.org

 ANT became a success maybe 

even more than Tomcat. 

ANT (

http://jakarta.apache.org/ant

) is a pure Java build system taking one or 

several XML files as input telling ANT what and how to build your application. This build 

file (by default named  build.xml ) contains three parts: 

Definition of properties which can (if setup) be overwritten by another file 

List of build in tasks to compile, jar, copy etc. 

List of targets and the dependencies to none, one or more other targets 

ANT starts with the specified or the main target (if not specified) and creates graph of the 

dependent targets (directly or indirectly dependent of the specified target). Then the targets 

are executed in reverse order (from the farthes away to the specified target). Finally each 

dependent target is executed once and only once. 

Normally it is the best practice to adjust a build file instead of writing your own. But in 

order to write a build file from scratch create the project (root element) first, then the main 

target, define its dependencies, create these targets and repeat the last two steps as 

necessary. Try to avoid static text (paths, values, etc.) and use ANT properties instead. 

These properties can be changed on a central place (where they are defined) and can be 

overwritten from a properties file (if enabled in the build file). This properties file enables 

clients to change settings without changing files in a CVS repository etc. 

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