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Jetty/Feature/NPN
Contents
Introduction
The Jetty project provides an implementation of the Next Protocol Negotiation TLS Extension (NPN) for OpenJDK 7 or greater.
Jetty's NPN implementation, although hosted under the umbrella of the Jetty project, is independent of Jetty (the Servlet Container), and can be reused in any other Java network server.
Feature
JVM Startup Usage
In order to enable NPN support, you need to start the JVM with:
java -Xbootclasspath/p:<path_to_npn_boot_jar> ...
where path_to_npn_boot_jar is the path on file system for the NPN Boot jar file, for example one at the following Maven coordinates org.mortbay.jetty.npn:npn-boot.
API Usage
Applications needs to interact with the negotiation of the next protocol performed by the NPN TLS extension. For example, server applications need to know whether the client supports NPN, and client applications needs to know the list of protocols supported by the server, and so on.
In order to provide this interaction, Jetty's NPN implementation provides an API to applications, hosted at Maven coordinates org.eclipse.jetty.npn:npn-api.
This dependency needs to be declared as "provided", because it is already included in the npn-boot jar (see section above) and therefore will be available in the boot classpath.
The API is composed by a single class, org.eclipse.jetty.npn.NextProtoNego, and applications need to register instances of SSLSocket or SSLEngine with a client or server provider (depending on whether the application is a client or server application).
Client Example