code: public void error( String messagePattern, Object arg1, Object arg2 )
      {
          if( m_delegate.isErrorEnabled() )
          {
              String msgStr = MessageFormatter.format( messagePattern, arg1, arg2 );
              m_delegate.error( msgStr, null );
          }
      }
docs: Log a message with the <code>ERROR</code> level with message formatting
  done according to the messagePattern and the arguments arg1 and arg2.
  <p>
  This form avoids superflous parameter construction. Whenever possible,
  you should use this form instead of constructing the message parameter
  using string concatenation.
  
  @param messagePattern The message pattern which will be parsed and formatted
  @param arg1           The first argument to replace the first formatting element
  @param arg2           The second argument to replace the second formatting element
  
  @since 1.3