This project is a minimal but functional OAuth2 Authorization Server (token issuer) and Resource Server (protected API). It uses Spring Boot to provide an embedded servlet container and for defaulting a load of configuration, so you should be up and running with it very quickly.
Building
You need Java (1.7 or better) and Maven (3.0.5 or better):
$ mvn package
$ java -jar target/*.jar
...
<Authorization Server starts and listens on port 8080>
<Resource Server starts and listens on port 8090>
Here are some curl commands to use to get started:
$ curl -H "Accept: application/json" my-client-with-secret:secret@localhost:8080/oauth/token -d grant_type=client_credentials
{... "access_token": "b561ff06-4259-466e-92d8-781db1a51901", ...}
$ TOKEN=b561ff06-4259-466e-92d8-781db1a5190
$ curl -H "Authorization: Bearer $TOKEN" localhost:8090/
Hello World