title: Error using checkstyle/google_checks.xml with maven-checkstyle-plugin
body: <p>I am trying to use <a href="https://github.com/checkstyle/checkstyle" rel="noreferrer">checkstyles</a> <a href="https://github.com/checkstyle/checkstyle/blob/master/google_checks.xml" rel="noreferrer">google_checks.xml</a> with <a href="http://maven.apache.org/plugins/maven-checkstyle-plugin/" rel="noreferrer">maven-checkstyle-plugin</a>. If I use the google_checks.xml with the latest checkstyle intelliJ plugin everything is correct but when I try configurating it via maven-checkstyle plugin I get this error:</p>
  
  <pre><code>[ERROR] Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:2.13:check (default-cli) on project XX_XX_XX: Failed during checkstyle configuration: cannot initialize module TreeWalker - Unable to instantiate AvoidEscapedUnicodeCharacters:
  Unable to instantiate AvoidEscapedUnicodeCharactersCheck 
  </code></pre>
  
  <p>My pom.xml looks like this:</p>
  
  <pre><code>   &lt;project xmlns="http://maven.apache.org/POM/4.0.0"
              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
              xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"&gt;
  &lt;properties&gt;
      [...]
      &lt;checkstyle.file.path&gt;develop/checkstyle/google_checks.xml&lt;/checkstyle.file.path&gt;
  &lt;/properties&gt;
  [...]
  &lt;build&gt;
      &lt;plugins&gt;
          [...]
          &lt;plugin&gt;
              &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
              &lt;artifactId&gt;maven-checkstyle-plugin&lt;/artifactId&gt;
              &lt;version&gt;2.13&lt;/version&gt;
              &lt;configuration&gt;
                  &lt;configLocation&gt;${checkstyle.file.path}&lt;/configLocation&gt;
                  &lt;failOnViolation&gt;false&lt;/failOnViolation&gt;
              &lt;/configuration&gt;
          &lt;/plugin&gt;
      &lt;/plugins&gt;
  &lt;/build&gt;
  &lt;reporting&gt;
      &lt;plugins&gt;
          &lt;plugin&gt;
              &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
              &lt;artifactId&gt;maven-checkstyle-plugin&lt;/artifactId&gt;
              &lt;version&gt;2.9.1&lt;/version&gt;
              &lt;configuration&gt;
                  &lt;configLocation&gt;${checkstyle.file.path}&lt;/configLocation&gt;
                  &lt;failOnViolation&gt;false&lt;/failOnViolation&gt;
              &lt;/configuration&gt;
          &lt;/plugin&gt;
      &lt;/plugins&gt;
  &lt;/reporting&gt;
  </code></pre>
  
  <p></p>
  
  <p>Do you guys have some suggestions about what could be wrong?</p>