title: FilerException when building Java EE 6 Project
body: <p>I have a Java EE 6 Project in Netbeans 7 which runs fine when I compile and start it in the IDE. However, when I clean and build the project, I am getting a </p>
  
  <blockquote>
    <p><code>java.lang.RuntimeException</code>: <code>javax.annotation.processing.FilerException</code>: Attempt to recreate a file for type {<code>myclass</code>}</p>
  </blockquote>
  
  <p>(where <code>myclass</code> is always a JPA entity class).</p>
  
  <p>Which entity class it is changes if I change something in the code.</p>
  
  <p>I have no clue what might cause this error - can anyone provide an idea what to look at.</p>
  
  <p>The only extra lib I am using is Velocity.</p>
  
  <p><strong>Update</strong>: I am using two persistence units on the same database, one 'normal' one and one non transactional one. The non-transactional one I use for logging things to the database; with a commit after each insert of a log event.</p>
  
  <p>When I change that and only use the one 'normal' PU, the project compiles fine. Could it be that the two PUs interfere with some optimization done by eclipselink?</p>
  
  <p>Here is the beginning of the stack trace:</p>
  
  <pre><code>An annotation processor threw an uncaught exception.
  Consult the following stack trace for details.
  java.lang.RuntimeException: javax.annotation.processing.FilerException: Attempt to recreate a file for type de.guj.contenthub.ftdts.entity.AgofEntry_
      at org.eclipse.persistence.internal.jpa.modelgen.CanonicalModelProcessor.process(CanonicalModelProcessor.java:407)
      at com.sun.tools.javac.processing.JavacProcessingEnvironment.callProcessor(JavacProcessingEnvironment.java:625)
      at com.sun.tools.javac.processing.JavacProcessingEnvironment.discoverAndRunProcs(JavacProcessingEnvironment.java:554)
      at com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:699)
      at com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:981)
      at com.sun.tools.
  </code></pre>