A Java library that implements application/problem+json
https://github.com/zalando/problem/compare/0.20.1..0.20.2
https://github.com/zalando/problem/compare/0.20.0..0.20.1
https://github.com/zalando/problem/compare/0.11.0..0.20.0
https://github.com/zalando/problem/compare/0.10.0..0.11.0
https://github.com/zalando/problem/compare/0.9.0..0.10.0
https://github.com/zalando/problem/compare/0.8.0..0.9.0
https://github.com/zalando/problem/compare/0.7.0..0.8.0
https://github.com/zalando/problem/compare/0.6.0..0.7.0
https://github.com/zalando/problem/compare/0.5.0..0.6.0
https://github.com/zalando/problem/compare/0.4.0..0.5.0