Since JNLP files are simply Java Web Start files that open applications through an Internet browser, any browser that works in Windows 8.1 will open a JNLP file as long as you have Java installed.

JEP 238: Multi-Release JAR Files extends the JAR file format to allow multiple, Java-release-specific versions of class/resource files to coexist in the same archive. This upgrade makes it easier for ...