`FlatFileItemReaderBuilder` reports error "Only one LineTokenizer option may be configured" when none are.

[mminella]

At line 472 of the FlatFileItemReaderBuilder it validates that not multiple LineTokenizers implementations have been configured. However, if the user has not configured one (validatorValue == 0 on that line), they get the same message implying that multiple have been configured. This error message should not be thrown if validatorValue == 0. The case of no LineTokenizer being configured is already handled at line 487 of that class anyways.

[santfirax]

Hello, I'd like to work on this.

[mminella]

If anyone is interested in working on this, please checkout the contribution guidelines here: https://github.com/spring-projects/spring-batch/blob/master/CONTRIBUTING.md

[santfirax]

Hello @mminella , can you take a look at this PR? #3689

[mminella]

Thanks to @santfirax to addressing this in amazingly fast time! Resolved via #3689