By referring to https://jwt.io/ you can find jwt implementations in many languages including java. Also the site provide some comparison between these implementation (the algorithms they support and ....).
For java these are mentioned libraries:
- https://github.com/jwtk/jjwt
- https://github.com/auth0/java-jwt ( A tutorial at https://auth0.com/docs/server-apis/java)
- https://bitbucket.org/b_c/jose4j
- https://bitbucket.org/connect2id/nimbus-jose-jwt
