Acronym for Plain Old Java Object.
POJO, or Plain Old Java Object, is a normal Java object class (that is, not a JavaBean, EntityBean etc.) and does not serve any other special role nor does it implement any special interfaces of any of the Java frameworks. This term was coined by Martin Fowler, Rebbecca Parsons and Josh MacKenzie who believed that by creating the acronym POJO, such objects would have a “fancy name”, thereby convincing people that they were worthy of use.
Related slanbg: POJI, short for plain old java interface. It is used to enforce the idea of developing an API against interfaces instead of implementations.