This NER tool is described in the paper: Shaodian Zhang and Noémie Elhadad, Unsupervised Biomedical Named Entity Recognition: Experiments with Clinical and Biological Texts, JBI [link]

Features:

• Could be used in various biomedical NER tasks. The tool is domain independent.
• No training data needed. No rules needed. Need UMLS metathesaurus
• See README for more details

Java implemention with souce code: [version 1.2] [README]