Developers often seek solutions for their programming problems by retrieving existing questions on technical Q&A sites such as Stack Overflow. In many cases, they fail to find relevant questions due to the knowledge gap between the questions and the queries or feel it hard to choose the desired questions from the returned results due to the lack of explanations about the relevance. In this paper, we propose KGXQR, a knowledge graph based explainable question retrieval approach for programming tasks. It uses BERT-based sentence similarity to retrieve candidate Stack Overflow questions that are relevant to a given query. To bridge the knowledge gap and enhance the performance of question retrieval, it constructs a software development related concept knowledge graph and trains a question relevance prediction model to re-rank the candidate questions. The model is trained based on a combined sentence representation of BERT-based sentence embedding and graph-based concept embedding. To help understand the relevance of the returned Stack Overflow questions, KGXQR further generates explanations based on the association paths between the concepts involved in the query and the Stack Overflow questions. The evaluation shows that KGXQR outperforms the baselines in terms of accuracy, recall, MRR, and MAP and the generated explanations help the users to find the desired questions faster and more accurately.

Developers often ask how-to questions using search engines, technical Q&A communities, and interactive Q&A systems to seek help for specific programming tasks. However, they often do not formulate the questions in a specific way, making it hard for the systems to return the best answers. We propose an approach (TaskKG4Q) that interactively helps developers formulate a programming related how-to question. TaskKG4Q is using a programming task knowledge graph (task KG in short) mined from Stack Overflow questions, which provides a hierarchical conceptual structure for tasks in terms of [actions], [objects], and [constraints]. An empirical evaluation of the intrinsic quality of the task KG revealed that 75.0% of the annotated questions in the task KG are correct. The comparison between TaskKG4Q and two baselines revealed that TaskKG4Q can help developers formulate more specific how-to questions. More so, an empirical study with novice programmers revealed that they write more effective questions for finding answers to their programming tasks on Stack Overflow.

In this paper, we present OpenAPIDocGen2, a tool that generates on-demand class documentation based on source code and documentation analysis. For a given class, OpenAPIDocGen2 generates a combined documentation for it, which includes functionality descriptions, directives, domain concepts, usage examples, class/method roles, key methods, relevant classes/methods, characteristics and concepts classification, and usage scenarios.