The project seems to be using json-simple jar for handling JSON. I see that there's been no releases or activity for json-simple since early 2012 - https://mvnrepository.com/artifact/com.googlecode.json-simple/json-simple
Consider replacing with Jackson Json jar which has a large user base and community (used by Spark/Flink/Jersey and bunch of other projects) - https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core Thoughts ?
