I\'m using the Play! framework v2.3 (Java) and I want to add some user authentication to my web app, ie username/password for each user and a registration process.
I
There are a number of authentication libraries that already exist which cover many use cases. It'd be best to use something that's well established in the community.
Secure Social - This seems to be the most popular, with lots of documentation. (For both java and scala)
Deadbolt 2 - There are many implementation examples linked from that git repo. It seems a little more geared for java.
Play2 Auth - This is for scala only, but it is well documented and very flexible. (I personally use Play2 Auth)