1. A method, in a data processing system comprising a processor and a memory, for validating a candidate answer to an input question, the method comprising: generating, by the data processing system, a candidate answer to an input question using a natural language processing of the input question and a corpus of information from which the candidate answer is identified; selecting, by the data processing system, a validator to apply to the candidate answer based on a characteristic of a correct answer for the input question; applying, by the data processing system, the validator to the candidate answer to evaluate whether or not one or more criteria of the validator are satisfied by the candidate answer; generating, by the data processing system, validation information based the evaluation of whether or not criteria of the validator are met by the candidate answer; and storing, by the data processing system, the validation information in a validation status object associated with the input question, wherein the validator is one of a plurality of validators registered with a pluggable validator framework, and wherein registration of the validator with the pluggable validator framework comprises specifying for which answer type or answer extension type in an answer key data structure the validator corresponds to.