Solved - Java 8u101 update blocked by windows firewall

[skeptic Mike]

I wrote:

(17-02-2017 01:29)skeptic Mike Wrote:  Oracle have a rather strange way of organising Java on Windows so that you can run Java programs reasonably easily. If you run Java by starting a jar file through the file association, then you start Java in the directory in which it's installed, e.g. you actually run C:\Program Files (x86)\Java\jre1.8.0_121\bin\javaw.exe, if you start it from the command line by just typing e.g. javaw -jarfile myprogram.jar, then it starts the version in the path. Since Java 8 was released, this has been the javaw.exe file in c:\ProgramData\Oracle\Javapath, which is in the system path. Normally this makes no difference to anything, but if you have a firewall exception for any executable file such as javaw.exe, then windows uses the full path name to identify it.

As MarmiteSandwich found out, this isn't right. So, I've actually tested this on a newly install 64 bit Win 10 Pro. I installed 64bit Java Runtime using the standard Oracle off-line installer, and MinimServer using the .exe file downloaded today from the website. I ran MinimServer by the standard shortcut, and by launching explicitly using a javaw -jar command line. Then I waited for the Windows Security warning to see what firewall exception it suggested.


The results are:

Conventional launch: C:\program files\java\jre.1.8.0_121\bin\javaw.exe

via javaw -jar: C:\programdata\oracle\java\javapath_target_359687\javaw.exe

I was surprised by the last one. It turns out that the folder C:\programdata\oracle\java\javapath is a junction point, which points to the real folder C:\programdata\oracle\java\javapath_target_359687. I haven't the enthusiasm for redoing the whole thing with the previous update 101 of Java, but that version didn't create the junction point, but used symlinks in the C:\programdata\oracle\java\javapath folder to the real executables in the program files folder. Update 121 doesn't use symlinks, but copies or hard links (I don't know which, but they look the same)

So, although you can start MinimServer using javaw -jar, don't do it. It looks as though it will be more confusing than the conventional way. I did try winrun4j, as I've suggested elsewhere in this thread, and that did work as I thought it would.