J2SE Version (please include all output from java -version flag):
Java Web Start 11.0.2.84
Using JRE version 1.8.0-ea-b84 Java HotSpot(TM) 64-Bit Server VM

java version "1.8.0-ea"
Java(TM) SE Runtime Environment (build 1.8.0-ea-b84)
Java HotSpot(TM) 64-Bit Server VM (build 25.0-b25, mixed mode)

Does this problem occur on J2SE 6ux or 7ux?
   Yes

Operating System Configuration Information (be specific):
   OSX 10.8.4

Hardware Configuration Information (be specific):
   24" iMac early 2009

Bug Description:
     Previously JNLP files could be opened by click (or even automatically). Since 10.8.4 it is required to sign JNLP files with an Apple Developer ID. There is no description or way to do that especially for dynamically generated JNLP files. Signing the JAR file and providing a template JNLP as of "https://blogs.oracle.com/thejavatutorials/entry/signing_jar_files_with_a" does not comply to Apple terms.

Steps to Reproduce (be specific):
   create a simple JNLP file. Double click the file to open. See the error message.