title: Maven build failure when including Scalatest with Java
body: <p>I'm trying to use the scala-maven-plugin:3.1.0 with Java 1.5. However my maven build is failing with an incompatibility error. </p>
  
  <pre><code> Failed to execute goal net.alchim31.maven:scala-maven-plugin:3.1.0:compile (scala-compile-first) on project proj: Execution scala-compile-first of goal net.alchim31.maven:scala-maven-plugin:3.1.0:compile failed: Unable to load the mojo 'compile' in the plugin 'net.alchim31.maven:scala-maven-plugin:3.1.0' due to an API incompatibility: org.codehaus.plexus.component.repository.exception.ComponentLookupException: Bad version number in .class file
  </code></pre>
  
  <p>There is also an unsupported class version warning</p>
  
  <pre><code>WARNING: Error injecting: scala_maven.ScalaCompileMojo
  java.lang.UnsupportedClassVersionError: Bad version number in .class file
  </code></pre>
  
  <p>The documentation for the plugin says that it requires Java 1.5 so i dont see a problem there. I'm using Java 1.5 locally and also for my maven build.</p>
  
  <p>Any suggestions to where the problem is? I cant see where another version of Java could be used to compile any of my classes so I'm guessing its an incompatibility in one of the dependencies i have but I've had no luck finding it. I'm also importing the following dependency</p>
  
  <pre><code>&lt;dependency&gt;
              &lt;groupId&gt;org.scalatest&lt;/groupId&gt;
              &lt;artifactId&gt;scalatest_2.9.0-1&lt;/artifactId&gt;
              &lt;version&gt;2.0.M5&lt;/version&gt;
          &lt;/dependency&gt;
  </code></pre>