MinimWatch 2.0.12 for Mac gives JavaHomeError

[BB1]

@LiitleScarabee
Thanks for providing a direct download link.

@Simon
As an engineer, I'm always interested in why something doesn't work. JRE vs. JDK was just my educated guess without having any knowledge about programming Java apps. Does the JDK provide additional functionally required for MinimServer 2 which is not available in the JRE? Or is MinimServer 2 looking for Java in the wrong place?

I'm aware that there are Java applications relying on a specific Java version. Usually the required JRE version of these apps is part of their installer (and the app can use a hard-coded link to it), but as an end user I've never seen a Java app requiring the JDK until now. I'm just curious why MinimServer 2 for MacOS behaves differently…

[simoncn]

OK, here is the full story...

It is all about the install location and your educated guess about JRE vs JDK was correct.

The install location for Java on Mac (JDK and JRE) has changed a few times over the last few releases of Java. This makes it slightly tricky for MinimServer to find a suitable Java installation to use. The scheme used by MinimServer 0.8 doesn't work for Java 11 and later, so a change was needed.

The install location for Java depends on the Java version and on whether the JDK or JRE is installed. You can have multiple versions of the JDK installed at the same time. The /usr/libexec/java_home command gives the location of the latest version installed but (it turns out) it only does this for JDK installs, not for JRE installs. I didn't realise this because I always run with the JDK installed. Because of this, MinimServer 2.0.12 is not finding the JRE installation if there is one.

The JRE uses a different install location which (apparently) is hard-wired, so you can only have one version of the JRE installed. The JRE versions that MinimServer 2 supports are JRE 8, JRE 9 and JRE 10. (JRE 10 was the last version of the JRE.) The JDK versions that MinimServer 2 supports are JDK 8, JDK 9, JDK 10, JDK 11, JDK 12, JDK 13 and JDK 14.

It is possible to have both the JDK and JRE installed. It seems reasonable that MinimServer should check for both the JDK and JRE and compare versions, using the latest version of whichever of the JRE or JDK is available. If both are available and the versions are the same, it doesn't matter too much but we need to choose one and my tie-break vote goes to the JDK.

I am hoping that a new version of MinimServer 2 that does this will be available soon. I have written the code and I will test it with various combinations tomorrow.

[simoncn]

This change is now included in the 2.0.12 downloads for both MinimServer and MinimWatch. The launcher looks for a JRE as well as a JDK. If multiple JDKs are available, the highest version is used. If the JDK and JRE are both available, the higher version is used. If the JDK and JRE both have the same version, the JDK is used.

[GreenMtnGringo]

Hi Simon, great news, thanks, and thanks for the fast action. What should people do who installed MS2/MW2 v2.0.12 before the Java revisions?

[simoncn]

If MinimServer/MinimWatch is running, there is no need for them to do anything. If MinimServer/MinimWatch is not running because they have the JRE and not the JDK, they should install the new version.

[DavidL]

(26-05-2020 11:14)simoncn Wrote:  This change is now included in the 2.0.12 downloads for both MinimServer and MinimWatch. The launcher looks for a JRE as well as a JDK. If multiple JDKs are available, the highest version is used. If the JDK and JRE are both available, the higher version is used. If the JDK and JRE both have the same version, the JDK is used.

Thanks for clarifying this and defining a painless way forward for users.

[BB1]

(25-05-2020 23:27)simoncn Wrote:  OK, here is the full story...

Thank you very much for the full story and quickly providing a solution.

(26-05-2020 11:14)simoncn Wrote:  This change is now included in the 2.0.12 downloads for both MinimServer and MinimWatch. The launcher looks for a JRE as well as a JDK. If multiple JDKs are available, the highest version is used. If the JDK and JRE are both available, the higher version is used. If the JDK and JRE both have the same version, the JDK is used.

I can confirm that this is working as intended here. MinimServer 2 on my Mac mini works without any JDK installed and MinimWatch on my MacBook uses the JRE because of its higher version number.

Thanks again, Simon!

[lyapounov]

As for me, I downloaded new minimwatch, uninstalled the previous one, installed then launched the new minimwatch, got the usual Mac warning, and nothing, nada, no icon.

I had to launch minimwatch a second time to get the icon. Then all is perfect.

Mojave 10.14.6

[simoncn]

This is described in the installation instructions (step 8). I don't know why it happens. It doesn't seem to happen for other downloaded applications.

[simoncn]

I have found what is causing this. It will be fixed in the next Mac versions of MinimWatch and MinimServer.