title: maven shade plugin custom transformer
body: <p>Given <a href="https://maven.apache.org/plugins/maven-shade-plugin/examples/resource-transformers.html" rel="nofollow noreferrer">maven shade plugin resource transformers</a>, how can we create custom ones?</p>
  
  <p>I've tried adding the shade plugin to my pom:</p>
  
  <pre><code>&lt;dependency&gt;
      &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
      &lt;artifactId&gt;maven-shade-plugin&lt;/artifactId&gt;
      &lt;version&gt;2.4.2&lt;/version&gt;
  &lt;/dependency&gt;
  </code></pre>
  
  <p>And creating a class that implements ResourceTransformer. But when I run it, I get:</p>
  
  <blockquote>
    <p>[ERROR] Failed to execute goal
    org.apache.maven.plugins:maven-shade-plugin:2.4.1:shade (default) on
    project foo: Unable to parse configuration of mojo
    org.apache.maven.plugins:maven-shade-plugin:2.4.1:shade for parameter
    transformers: Cannot load implementation hint
    'test.transformer.TestTransformer' -> [Help 1]</p>
  </blockquote>
  
  <p>The transformer is on the same classpath as the project I'm running the build on, which, I'm guessing is the problem. Is there a way to add in an extension that brings in other transformers?</p>