code: public static AuthleteApi create(AuthleteConfiguration configuration)
      {
          for (String className : sKnownImpls)
          {
              try
              {
                  return create(configuration, className);
              }
              catch (Exception e)
              {
                  // Ignore.
              }
          }
  
          // No implementation was found.
          return null;
      }
docs: Create an instance of {@link AuthleteApi}.
  
  <p>
  This method repeats to call {@link #create(AuthleteConfiguration, String)}
  until one of the known classes is successfully instantiated.
  </p>
  
  <p>
  The classes listed below are the ones that the current implementation knows.
  </p>
  
  <ol>
  <li><code>com.authlete.jaxrs.api.AuthleteApiImpl</code><br/>
  (using JAX-RS 2.0 API, contained in <code>com.authlete:authlete-java-jaxrs</code>)
  <li><code>com.authlete.common.api.AuthleteApiImpl</code><br/>
  (using {@link java.net.HttpURLConnection HttpURLConnection}, contained in <code>com.authlete:authlete-java-common</code> since version 2.0)
  </ol>
  
  @param configuration
  Authlete configuration.
  
  @return
  An instance of {@link AuthleteApi}. If none of the known classes
  that implement {@code AuthleteApi} interface was successfully
  instantiated, {@code null} is returned.