In this example we are going to demonstrate how to use the basic form of the ALPN extension introduced in JDK 9. ALPN is used to negotiate the application protocol between the client and the server during TLS handshake.
In the source folder there is a BasicALPN project that provides an implementation of a simple TLS client and a TLS server.
Specify that the client supports the XMPP v1.1 protocol and the server supports the XMPP v1.1 and XMPP v1.2 protocols using the ALPN extension (hint: use the setApplicationProtocols() method on the proper instance in the provided implementation).
Use the compile.sh script to compile the project:
$ ./compile.sh
Run the compiled com.project.Server class with the run_server.sh script:
$ ./run_server.sh
Run the compiled com.project.Client class with the run_client.sh script and observe the negotiated protocol (must be XMPP v1.1):
$ ./run_client.sh