Based on the code of https://github.com/googlesamples/mlkit/tree/master/android/entityextraction, the ML kit, function Entity Extraction, cannot recognize dates in text written like "18/Mar" or "18/03". I think it should assume current year. Also it cannot identify hours written like "18h" or "18h00" or "18h00min" or "18h00".
As a beginner programmer, I expect to know how to solve it, if someone could help.