Checker framework is a great lightweight tool which could easily type check code having a dependency on a library if the library has already been annotated. Google Gson is a widely used library written in java to transform the Java objects to JSON (JavaScript Object Notation) and vice versa. This library has a total of 143 directories and 255 files out of which 208 are java files. This project could be an overall evaluation of the type-checkers on real code and can also help detect bugs or suggest improvements to the library being annotated. The main goal of the project

  1. Adding annotations to the Google Gson library for Nullness, Index and Interning checker.
  2. Adding missing annotations in JDK and reporting bugs if found any in the process.



Priti Chattopadhyay


  • Maximilian Gama
  • Michael Ernst