I think this is false positive
java:S2259 Community Edition version 9.9.1 (build 69595)
Hello @squestc and welcome to the Sonar Community!
Thank you for reporting this issue. Unfortunately, we are aware of many false positives raised by rule S2259 and the list contains already [SONARJAVA-2317] - Jira that mentions the scenario in which
isBlank() is used.
The rule S2259 is implemented on top of the Symbolic Execution engine that is not maintained, so mark it as won’t fix and ignore these issues for now. The good news is that a new engine, the Dataflow Bug Detection, is in development and will be soon available.
thanks a lot，respect