Looking at DefaultAllocationManagerOption [1], I see that we could prevent dummy NPEs when trying to convert an often not-set environment option into enums.
In my case, it was a bit painful to have this error, even if properly caught, because it was polluting debug when looking for unexpected NPEs. This was raising false positives.

  I was wondering if you were open to a pull request to change this little inconvenience?

  [1] https://github.com/apache/arrow/blob/master/java/memory/memory-core/src/main/java/org/apache/arrow/memory/DefaultAllocationManagerOption.java#L64-L82