Services in Nuxeo
All ECM features in Nuxeo EP are exposed as Java Services.
These services can be local (inside the same JVM) and most of them can also be called remotely via RMI if your target Application Server supports EJB3 remoting.

All services are defined by a Java Interface and are accessed via this interface.
Nuxeo Runtime provides a lookup system to access a Service:
This lookup call encapsulate the potential JNDI lookup to access a remote service if your application server and configuration require it.
If you want explicitly to access a local service you can also use:
Inside the Seam WebLayer, most common Nuxeo Services are also wrapped as Seam components so you can directly get them via injection:
How to know what services are available
Nuxeo EP is a big platform and it provides a lot of different services.
You can use Platform Explorer WebSite or platform explorer addon to see the services included in a given distribution of Nuxeo EP.
Listing ECM Services