I couldn't figure out how to run Java Web Start applications in Mozilla Firefox on Linux. There was nothing associated with the .jnlp files...

• Java 1.4 or greater must be installed.
• Click on the .jnlp file link and select "Open with Other Application"
• Select "Use a custom command", and click "Browse".
• Locate your java installation folder and select the file $JAVA_HOME/jre/javaws/javaws. or /usr/share/javaws/javaws.
• Click OK.

How can I open Web Start Console

• Start Java Web Start Application Manager
• From menu "Edit" -> "Preferences"...
• Select "Advanced".
• "Java Console" -> "Show Console".
• Click OK.