The id attribute of the buildfile's elements can be used to refer to them. This can be useful if you are going to replicate the same snippet of XML over and over again - using a <classpath> structure more than once, for example.
The following example:
<project ... > <target ... > <rmic ...> <classpath> <pathelement location="lib/"/> <pathelement path="${java.class.path}/"/> <pathelement path="${additional.path}"/> </classpath> </rmic> </target> <target ... > <javac ...> <classpath> <pathelement location="lib/"/> <pathelement path="${java.class.path}/"/> <pathelement path="${additional.path}"/> </classpath> </javac> </target> </project>could be rewritten as:
<project ... > <path id="project.class.path"> <pathelement location="lib/"/> <pathelement path="${java.class.path}/"/> <pathelement path="${additional.path}"/> </path> <target ... > <rmic ...> <classpath refid="project.class.path"/> </rmic> </target> <target ... > <javac ...> <classpath refid="project.class.path"/> </javac> </target> </project>
All tasks that use nested elements for PatternSets, FileSets or path-like structures accept references to these structures as well.