I have been looking for a simple to follow tutorial or example of implementing a JSON Web Token (JWT) authentication system using Java (server-side). I am building an Ionic (Cordova) app that requires auto-sign-in capability, JWT seems to be the most secure way of accomplishing this. Saving the user's username and password locally is obviously pretty insecure. I have looked at OAuth 2.0, which looks promising, although I can't find much solid documentation. Has anyone here successfully implemented OAuth 2.0 in Java? I think the client-side part using AngularJS should be fairly straightforward, but the server-side part looks daunting. I have never worked with tokens, so maybe it's not as hard as it seems. My boss doesn't want to install Maven on our server, so I'm struggling to find a token solution.