Mechanisms are provided, in a Question and Answer (QA) system comprising a processor and a memory, for debugging code. An input question identifying an error during execution of code is processed by the QA system using a corpus corresponding to a software product associated with the code, thereby generating a first candidate answer set. The QA system processes the input question using a code change record repository identifying changes to the code performed over time to generate a second candidate answer set. The QA system generates a final answer to the input question based on the first and second candidate answer sets and outputs the final answer to the input question. The final answer to the input question identifies at least one of a source, in the code, of the error or a solution to resolving the error.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A method, in a Question and Answer (QA) system comprising a processor and a memory, for debugging code, the method comprising: receiving, by the QA system, an input question identifying an error encountered during execution of code; processing, by the QA system, the input question using a corpus of information content corresponding to a software product associated with the code to generate a first set of candidate answers for the input question; processing, by the QA system, the input question using a code change record repository identifying changes to the code performed over time to generate a second set of candidate answers for the input question; generating, by the QA system, a final answer to the input question based on the first set of candidate answers and the second set of candidate answers; and outputting, by the QA system, the final answer to the input question, wherein the final answer to the input question identifies at least one of a source, in the code, of the error or a solution to resolving the error. 2. The method of claim 1, wherein receiving the input question identifying the error encountered during execution of code further comprises receiving, along with the input question, code error information generated during execution of the code or as a result of the code that identifies characteristics of the error encountered. 3. The method of claim 2, wherein the code error information comprises at least one of stack trace information or error log entries generated in response to encountering the error during execution of the code. 4. The method of claim 1, wherein: the software product associated with the code is a previous version of the code, the code is code that is modified from the previous version of the code, the corpus of information content comprises documentation for documenting the operation of the previous version of the code, and the code change record repository identifies differences between the code and the previous version of the code and corresponding effective dates/times of the differences. 5. The method of claim 1, wherein processing the input question using a code change record repository comprises: determining an effective date/time of first evidence passages, from the corpus of information content, used to generate the first set of candidate answers for the input question; identifying one or more second evidence passages from the code change record repository having corresponding timestamps that are later in time than the effective date/time of the first evidence passages; and generating the second set of candidate answers for the input question based on the one or more second evidence passages. 6. The method of claim 5, wherein the one or more second evidence passages identify changes to the code that occurred after the effective date/time of the first evidence passages. 7. The method of claim 5, wherein identifying the effective date/time of the first evidence passages comprises: comparing dates/times associated with each of the first evidence passages to generate an comparison result, wherein the comparison result identifies at least one of a latest date/time of evidence passages within the first evidence passages, an oldest date/time of evidence passages within the first evidence passages, and an average of date/times associated with evidence passages within the first evidence passages; and setting the effective date/time for the first evidence passages to a value corresponding to the comparison result. 8. The method of claim 2, wherein processing the input question using a corpus of information content comprises: extracting, by one or more annotators operating on the input question, code debugging features from at least one of the input question or the code error information, wherein each of the one or more annotators comprise logic specifically configured to extract a particular type of code debugging feature. 9. The method of claim 8, wherein extracting code debugging features comprises at least one of: extracting a class name, method name, or line of code identifier associated with the encountered error; analyzing a stack trace in the code error information to identify at least one method that was being called at the time of the encountered error; or performing natural language processing on a name of a class or method in a stack trace to identify a nature of the encountered error from text in the name of the class or method. 10. The method of claim 1, wherein the input question is one of a user entered natural language description of the encountered error or an automatically generated report of the encountered error. 11. A computer program product comprising a computer readable storage medium having a computer readable program stored therein, wherein the computer readable program, when executed on a Question and Answer (QA) system comprising a processor and a memory, causes the QA system to: receive an input question identifying an error encountered during execution of code; process the input question using a corpus of information content corresponding to a software product associated with the code to generate a first set of candidate answers for the input question; process the input question using a code change record repository identifying changes to the code performed over time to generate a second set of candidate answers for the input question; generate a final answer to the input question based on the first set of candidate answers and the second set of candidate answers; and output the final answer to the input question, wherein the final answer to the input question identifies at least one of a source, in the code, of the error or a solution to resolving the error. 12. The computer program product of claim 11, wherein computer readable code further causes the QA system to receive, along with the input question, code error information generated during execution of the code or as a result of the code that identifies characteristics of the error encountered. 13. The computer program product of claim 12, wherein the code error information comprises at least one of stack trace information or error log entries generated in response to encountering the error during execution of the code. 14. The computer program product of claim 11, wherein: the software product associated with the code is a previous version of the code, the code is code that is modified from the previous version of the code, the corpus of information content comprises documentation for documenting the operation of the previous version of the code, and the code change record repository identifies differences between the code and the previous version of the code and corresponding effective dates/times of the differences. 15. The computer program product of claim 11, wherein computer readable code causes the QA system to process the input question using a code change record repository at least by: determining an effective date/time of first evidence passages, from the corpus of information content, used to generate the first set of candidate answers for the input question; identifying one or more second evidence passages from the code change record repository having corresponding timestamps that are later in time than the effective date/time of the first evidence passages; and generating the second set of candidate answers for the input question based on the one or more second evidence passages. 16. The computer program product of claim 15, wherein the one or more second evidence passages identify changes to the code that occurred after the effective date/time of the first evidence passages. 17. The computer program product of claim 15, wherein computer readable code causes the QA system to identify the effective date/time of the first evidence passages at least by: comparing dates/times associated with each of the first evidence passages to generate an comparison result, wherein the comparison result identifies at least one of a latest date/time of evidence passages within the first evidence passages, an oldest date/time of evidence passages within the first evidence passages, and an average of date/times associated with evidence passages within the first evidence passages; and setting the effective date/time for the first evidence passages to a value corresponding to the comparison result. 18. The computer program product of claim 12, wherein computer readable code further causes the QA system to process the input question using a corpus of information content at least by: extracting, by one or more annotators operating on the input question, code debugging features from at least one of the input question or the code error information, wherein each of the one or more annotators comprise logic specifically configured to extract a particular type of code debugging feature. 19. The computer program product of claim 18, wherein computer readable code causes the QA system to extract code debugging features by at least one of: extracting a class name, method name, or line of code identifier associated with the encountered error; analyzing a stack trace in the code error information to identify at least one method that was being called at the time of the encountered error; or performing natural language processing on a name of a class or method in a stack trace to identify a nature of the encountered error from text in the name of the class or method. 20. A Question and Answer (QA) system, comprising: a processor; and a memory coupled to the processor, wherein the memory comprises instructions which, when executed by the processor, cause the processor to: receive an input question identifying an error encountered during execution of code; process the input question using a corpus of information content corresponding to a software product associated with the code to generate a first set of candidate answers for the input question; process the input question using a code change record repository identifying changes to the code performed over time to generate a second set of candidate answers for the input question; generate a final answer to the input question based on the first set of candidate answers and the second set of candidate answers; and output the final answer to the input question, wherein the final answer to the input question identifies at least one of a source, in the code, of the error or a solution to resolving the error.