java - Generate minimized jar with only used classes

Question

I'm in need of creating the minimal jar of utils library for use in Android. I'm using some methods from apache commons libraries (such as IOUtils, StringUtils). However, each such usage makes me import the whole library (commons-lang, commons-io etc.) which is absolutely acceptable under Tomcat (war's are mamoot-sized anyway), but absolutely unacceptable for Android project.

So, my aim is, to pack all used classes from dependencies into one jar - but only that classes that are needed. I remember once being in touch with maven plugin that done that task, unfortunatelly I can't remember its name nor find it via Google.

So please, do you know maven plugin that will do such minimization of dependencies, or any stand-alone tool that will do the same?

Answer 1

The maven plugin you can't remember is probably Apache Maven Shade Plugin, there is minimizeJar option. As Andreas_D noticed, this won't include classes, loaded with Class.forName, so you will need to implicity say in configuration, that you need them. Here is how i made maven to include jdbc driver in my single jar:

<filter>
  <artifact>net.sourceforge.jtds:jtds</artifact>
    <includes>
      <include>**</include>
    </includes>
</filter>