The JNLP is used for launching applications on a desktop client using resources located on a web server. JNLP clients include Java Web Start and Java plug-in software because they are able to launch applets that are remotely hosted. This protocol is instrumental in launching RIAs.

RIAs (short for Rich Internet Applications), when launched with JNLP, have access to the various JNLP APIs that, with user permission, can access the user's desktop.

The JNLP specification was updated in Java 9. There are four specific updates as detailed in the following sections.