An installed version of Java has a feature known as 'Java Web Start', which allows opening files ending with the jnlp file extension.
When I try dragging a jnlp file to JavaPortableLauncher.exe it says:
--------------------------- Java Virtual Machine Launcher --------------------------- Error: Invalid or corrupt jarfile C:\Users\Tixue\Downloads\launch.jnlp --------------------------- OK ---------------------------
Can I open .jnlp files with jPortable? If so, how? and if not, why not?
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Everything that I've seen about launching jnlp files directly indicates that this only works with the installed version of Java if/when file associations are set to enable a direct software launch. This would not be possible with the portable java installation in Windows 10 as Microsoft does not allow file associations to set for anything other than 'fully' installed software for security reasons, i.e. the specific prevention of non-installed software from altering a user's existing system settings.
The only possible work-around I can suggest would be to try one of the portable File Manager's that implements some form of internal file associations. Oracle's website has guidance on how to make calls to the feature in the installed version of Java. Alternatively, you might try using the same guidance to write a script routine to direct the software file to the appropriate Java Portable feature, which should presumably be present in the Java Portable installation, as the software downloaded and unpacked by PortableApps is identical to that which would be used for a full local installation. The javaws.exe file is present in PortableApps Java installations, which suggests that all of the necessary elements Oracle mentions in its development guidance do exist.
Start a command prompt
Navigate to the java installation commonfiles\java\bin folder where javaws.exe is
javaws.exe PATH_TO_JNLP -J
Voila!
if you add the switch -system to it, it'll save the file to cache, which can save time.
So we get:
Start a command prompt
Start a command prompt
Navigate to the java installation commonfiles\java\bin folder where javaws.exe is
javaws.exe -system "PATH_TO_JNLP -J"
Experimental jnlp support has been added in today's jPortable Launcher 5.0 release. Note that it is untested and data will likely not be portable.
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