ANT: ways to include libraries and license issues - ant

Question

I have been trying to use Ant to compile and ready a project for distribution. I have encountered several problems along the way that I have been finally able to solve but the solution leaves me very unsatisfied. First, let me explain the set-up of the project and its dependencies.
I have a project, lets call it Primary which depends on a couple of libraries such as the fantastic Guava. It also depends on another project of mine, lets call it Secondary. The Secondary project also features some dependencies, for example, JDOM2. I have referenced the Jar I build with Ant in Primary.
Let me give you the interesting bits of the build.xml so you can get a picture of what I am doing:
<project name="Primary" default="all" basedir=".">
<property name='build' location='dist' />
<property name='application.version' value='1.0'/>
<property name='application.name' value='Primary'/>
<property name='distribution' value='${application.name}-${application.version}'/>
<path id='compile.classpath'>
<fileset dir='libs'>
<include name='*.jar'/>
</fileset>
</path>
<target name='compile' description='Compile source files.'>
<javac includeantruntime="false" srcdir="src" destdir="bin">
<classpath refid='compile.classpath'/>
</javac>
<target>
<target name='jar' description='Create a jar file for distribution.' depends="compile">
<jar destfile='${build}/${distribution}.jar'>
<fileset dir="bin"/>
<zipgroupfileset dir="libs" includes="*.jar"/>
</jar>
</target>
The Secodnary project's build.xml is nearly identical except that it features a manifest as it needs to run:
<target name='jar' description='Create a jar file for distribution.' depends="compile">
<jar destfile='${dist}/${distribution}.jar' basedir="${build}" >
<fileset dir="${build}"/>
<zipgroupfileset dir="libs" includes="*.jar"/>
<manifest>
<attribute name="Main-Class" value="lu.tudor.ssi.kiss.climate.ClimateChange"/>
</manifest>
</jar>
</target>
After I got it working, trying for many hours to not include that dependencies as class files but as Jars, I don't have the time or insight to go back and try to figure out what I did wrong. Furthermore, I believe that including these libraries as class files is bad practice as it could give rise to licensing issues while not packaging them and merely including them in a directory along the build Jar would most probably not (And if it would you could choose not to distribute them yourself).
I think my inability to correctly assemble the class path, I always received NoClassDefFoundError for classes or libraries in the Primary project when launching Second's Jar, is that I am not very experienced with Ant. Would I require to specify a class path for both projects? Specifying the class path as . should have allowed me to simply add all dependencies to the same folder as Secondary's Jar, should it not?

Answer 1

You may use the MANIFEST.MF "Class-Path: " to cross-reference your jars.
If they are all in the same directory this will probably work as follows (using it in both projects!):
<target name='jar' description='Create a jar file for distribution.' depends="compile">
<pathconvert property="manifest.classpath" pathsep=" ">
<path refid="compile.classpath" />
<flattenmapper />
</pathconvert>
<jar destfile='${build}/${distribution}.jar'>
<fileset dir="bin"/>
<manifest>
<attribute name="Class-Path" value="${manifest.classpath}"/>
</manifest>
</jar>
</target>
This way you can tell the java runtime environment that your jar needs others to work, expecting them to be in the same directory as the jar you are trying to run.
As a result your primary.jar should have secondary.jar in it's classpath and secondary.jar should have guava.jar in it's classpath.
Another way to create the string may be ants manifestclasspath task (https://ant.apache.org/manual/Tasks/manifestclasspath.html) that can handle subdirectories.
If you are goin to use more and more libraries, you may want to have a closer look at ivy or even maven.