title: Sonar S00119 rename generic name allows digits
body: <p>I have the following code </p>
  
  <pre><code>protected &lt;TProperty&gt; TProperty getPropertyFromConfig(SubConfiguration cfg,
          String property, TProperty defaultValue, Class&lt;TProperty&gt; clazz)
  </code></pre>
  
  <p>Which seems readable, but Sonar warns about generic name:</p>
  
  <blockquote>
  <pre><code>Rename this generic name to match the regular expression '^[A-Z][0-9]?$'
  </code></pre>
  </blockquote>
  
  <p>But the description statement is about using a <strong>single letter</strong> </p>
  
  <blockquote>
    <p>Following the established convention of <strong>single-letter type parameter</strong> names helps users and maintainers </p>
  </blockquote>
  
  <p>So it allows also a digit:</p>
  
  <pre><code>protected &lt;T1&gt; TProperty getPropertyFromConfig(SubConfiguration cfg,
          String property, T1 defaultValue, Class&lt;T1&gt; clazz)
  </code></pre>
  
  <p>Should it allows generic type name with digits?</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>The duplicate questions/answers doesn't refer to adding digit to generic name</p>