How to recognize a named entity that is lowcase such as kobe bryant by CoreNLP?

First off, you do have to accept that it is harder to get named entities right in lowercase or inconsistently cased English text than in formal text, where capital letters are a great clue. Nevertheless, there are things that you must do to get CoreNLP working fairly well with lowercase text – the default models are trained to work well on well-edited text. If you are working with properly edited text, you should use our default English models. If the text that you are working with is (mainly) lowercase or uppercase, then you should use one of the two solutions presented below. If it's a real mixture (like much social media text), you might use the truecaser solution below, or you might gain by using both the cased and caseless NER models (as a long list of models given to the ner.model property).