In GeneratorMapper, two return statements are shifted by a line so that they end up in a if (LOG.isWarnEnabled()) block. Therefore a change of the log level will change the behavior of the generator, i.e. an URL where an IndexFilters throws an exception will still be generated.
The attached patch removes the if block completely by using SLF4J's placeholders. This avoids the unnecessary string concatenations that made the if necessary.