Signpost is the easy and intuitive solution for signing HTTP messages on the Java platform in conformance with the OAuth Core 1.0a standard.
Using Signpost is as simple as it could possibly get -- all actions are executed with only a few lines of code.
Signpost tries to be as unobtrusive as possible. Unlike other implementations, Signpost does not wrap the entire HTTP layer and hides its features from the client.
Since version 1.1, Signpost comes in modules. Apart from the core module, which you always need, you can download additional modules to support other HTTP messaging libraries than the one coming with the standard Java platform