title: Can't use jcl-over-slf4j in Java 9
body: <p>I've problem replace commons-logging with jcl-over-slf4j in Java 9 Module System.
  I've exclude commons-logging from maven and add jcl-over-slf4j as dependency:</p>
  
  <pre><code>  &lt;dependency&gt;
      &lt;groupId&gt;org.apache.commons&lt;/groupId&gt;
      &lt;artifactId&gt;commons-configuration2&lt;/artifactId&gt;
      &lt;version&gt;2.3&lt;/version&gt;
      &lt;exclusions&gt;
        &lt;exclusion&gt;
          &lt;groupId&gt;commons-logging&lt;/groupId&gt;
          &lt;artifactId&gt;commons-logging&lt;/artifactId&gt;
        &lt;/exclusion&gt;
      &lt;/exclusions&gt;
    &lt;/dependency&gt;
  
    &lt;dependency&gt;
      &lt;groupId&gt;org.slf4j&lt;/groupId&gt;
      &lt;artifactId&gt;jcl-over-slf4j&lt;/artifactId&gt;
      &lt;version&gt;1.8.0-beta2&lt;/version&gt;
    &lt;/dependency&gt;
  </code></pre>
  
  <p>As I can see, the commons-configuration2 is an auto named module and the jcl-over-slf4j is an application module.</p>
  
  <p>If I leave the module jcl-over-slf4j out of module-info.java, I got this NoClassDefFoundError error, the jcl-over-slf4j is on the classpath somehow the library can't see it:</p>
  
  <pre><code> Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/Log
  at org.apache.commons.configuration2@2.3/org.apache.commons.configuration2.io.FileSystem.&lt;clinit&gt;(FileSystem.java:37)
  </code></pre>
  
  <p>If I add the jcl-over-slf4j to the module-info.java, I got this illegal access error,:</p>
  
  <pre><code>requires transitive org.apache.commons.logging;
  </code></pre>
  
  <p>Which org.apache.commons.logging module is in fact the jcl-over-slf4j module.</p>
  
  <pre><code>xception in thread "main" java.lang.IllegalAccessError: class org.apache.commons.configuration2.io.ConfigurationLogger (in module org.apache.commons.configuration2) cannot access class org.apache.commons.logging.impl.NoOpLog (in module org.apache.commons.logging) because module org.apache.commons.logging does not export org.apache.commons.logging.impl to module org.apache.commons.configuration2
  at org.apache.commons.configuration2@2.3/org.apache.commons.configuration2.io.ConfigurationLogger.newDummyLogger(ConfigurationLogger.java:115)
  </code></pre>
  
  <p>Which I don't understand, the commons-configuration2 shoulde be able to access it, and I'm stuck here. Any help is welcome.</p>