Can't open .jnlp file even though I have a JRE installed

Question

I have downloaded a.jnlp file, but when opening it with Java Web Start I am greeted with the following message: "To open this Web Start application you need to download the Java Runtime Environment." The OS is macOS 10.15.6.

Running java -version in the Terminal outputs

java version "13.0.1" 2019-10-15
Java(TM) SE Runtime Environment (build 13.0.1+9)
Java HotSpot(TM) 64-Bit Server VM (build 13.0.1+9, mixed mode, sharing)

So I do, in fact, have a JRE installed. What can I do to open the file?

Answer 1

JNLP refers to the file format defined for Java Webstart technology. Check out https://openwebstart.com/ :

Java Web Start (JWS) was deprecated in Java 9, and starting with Java 11, Oracle removed JWS from their JDK distributions. [...] This is why we decided to create OpenWebStart, an open source reimplementation of the Java Web Start technology.

You will either have to downgrade your Java installation or add OpenWebStart.

Answer 2

I had this same issue today while running on Windows. The.jnlp file wasn't recognizing the that JRE was installed even with Java Web Start running.

I went ahead and reinstalled JRE 8 and the.jnlp file launched just fine.