I'm having the same problem.
I have a Vantage Pro2 weather station connected to my Mac computer through WeatherLink. I upgraded my operating system from El Capitan (10.11.6) to Mojave (10.14.3). I now know that was a mistake because Weatherlink cannot be run under Mojave. Like dave99ag, I installed the legacy Java, but still get: java.lang.UnsatisfiedLinkError: /Applications/Mac OSX WeatherLink/WeatherLink.app/Contents/Resources/Java/libjspMacOSX.jnilib: no suitable image found.
Also like dave99ag, I strongly suspect that Mojave identifies Weatherlink as able to run in 64-bit mode, when in fact it can’t. The evidence for the misidentification of bit mode is that in “About This Mac” when you select “System Report…” and then “Software” “Applications”, it lists WeatherLink with 64-Bit (intel) = “yes”. This indicates to me that Mojave thinks that “yes” this can be run in 64-Bit mode. When it tries, however, it gives the “java.lang” error (even though I installed the legacy java version).
I’ve searched on the web for a way to change the 64-bit mode from “yes” to “no”, but without success. I can find no way to force Mojave to run Weatherlink in 32-bit mode. I also do not have another computer with an older operating system on it (dave99ag was fortunate in that regard), so I’m in real trouble.
Can anyone suggest a way to do one of the following:
1) force Mojave to run Weatherlink in 32-bit mode
2) download the data using some software other than WeatherLink, so that my meteorological record can remain continuous?
3) enable me to restore my old El Capitan operating system
I would really like to keep my meteorological records continuous to time is of the essence.
[Unfortunately, Mojave will not allow you reinstall old OS versions (see
https://www.macworld.co.uk/news/mac-software/impossible-download-old-macos-3684588/ ). I’ve tried to restore El Capitan but can’t.]
thank you.