There are a few tools available that may assist in opening JNLP files without Java:
1. IcedTea-Web
IcedTea-Web is an open-source implementation of the Java Web Start technology and allows users to run JNLP applications without the need for Oracle’s Java Runtime Environment. This tool can be a great choice for users who want a free alternative.
2. OpenWebStart
OpenWebStart is another alternative that provides a way to run JNLP applications without needing Java installed. It is designed to be a drop-in replacement for Java Web Start, making it easy for users to switch.