MQTT-SPY : [3] GUI : PROBLEMS getting version information - [2] compatibility of version JavaFX / openjfx - [1] Could not find or load main class

[droopy4u]

It started with : but finally end with problems in the GUI (see point 3)

1. It originally started with :

Error: Could not find or load main class pl.baczkowicz.mqttspy.Main

more information about my troubleshooting -

The ERROR :

tech@LinuMint:SOFT $ java -jar ./mqtt-spy-1.0.1-beta-b18-jar-with-dependencies.jar                                                
Error: Could not find or load main class pl.baczkowicz.mqttspy.Main

2. compatibility of version JavaFX / openjfx

### Finally I found this problem :
for more information --> see point 5. - troubleshooting

has been compiled by a more recent version of the Java Runtime (class file version 54.0), this version of the Java Runtime only recognizes class file versions up to 52.0

Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError: javafx/application/Application has been compiled by a more recent version of the Java Runtime (class file version 54.0), this version of the Java Runtime only recognizes class file versions up to 52.0

SOLUTION

https://forums.linuxmint.com/viewtopic.php?p=1826127#p1826127 - Thu Jul 07, 2011 8:47 am - by ramk

using the same installed the appropriate version of openjdk 8, openjfx 8 and the related "correct" dependencies.

apt-cache show openjfx
sudo apt-get -V install openjfx=8u161-b12-1ubuntu2 libopenjfx-java=8u161-b12-1ubuntu2 libopenjfx-jni=8u161-b12-1ubuntu2

So I followed the information and tried out for 'my' version '8u252-b09', but without success:

$ sudo apt-get -V install openjfx=8u252-b09-1ubuntu2 libopenjfx-java=8u252-b09-1ubuntu2 libopenjfx-jni=8u252-b09-1ubuntu2
   
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Version 8u252-b092-1ubuntu2' for 'openjfx' was not found
E: Version '8u252-b09-1ubuntu2' for 'libopenjfx-java' was not found
E: Version '8u252-b09-1ubuntu2' for 'libopenjfx-jni' was not found

---

But how to find out which versions are available; ex '8u161-b12' ?

apt-get -V install openjfx=8u161-b12-1ubuntu2 libopenjfx-java=8u161-b12-1ubuntu2 libopenjfx-jni=8u161-b12-1ubuntu2

The installed versions :

$ apt-cache policy openjfx        
openjfx:
  Installed: 8u161-b12-1ubuntu2
  Candidate: 11.0.2+1-1~18.04.2
  Version table:
     11.0.2+1-1~18.04.2 500
        500 http://archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages
        500 http://security.ubuntu.com/ubuntu bionic-security/universe amd64 Packages
 *** 8u161-b12-1ubuntu2 500
        500 http://archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        100 /var/lib/dpkg/status

If I search via the package on the site of ubuntu; openjfx, I don't find '8u161-b12-1ubuntu2'

the package on the site of ubuntu available ; openjfx

3. GUI : ERROR / PROBLEMS getting version information / update version

Finally I have the GUI MQTT SPY up and running, but still have some problems - see image.

And I'm afraid that I also have problems, with making a network connection.
But about that, I have to check that I didn't make a fault (I'm a beginner at MQTT).

https://i.stack.imgur.com/SZ3fu.png

[colin713]

Did you get a resolution with this issue. I have the same problem: I get the GUI as shown: Error getting version info. Also I am unable to connect to any of the brokers.
Using windows 10. I'm assuming the Java RTE supports FX, ?

C:\Users...>java -version
java version "1.8.0_321"
Java(TM) SE Runtime Environment (build 1.8.0_321-b07)
Java HotSpot(TM) 64-Bit Server VM (build 25.321-b07, mixed mode)

[bmw-biker]

Same issue here. Any suggestions ?
Also the "please support" notification window hangs on top all windows and will not close.
Meanwhile we have Win 10 22H2, Mqtt Spy 1.0 and JRE 8 361

[riker65]

looks like after some updated I also run again into those issues, can not get it started on ubunut 20
running
/usr/lib/jvm/java-14-openjdk-amd64/bin/java -cp "mqtt-spy-0.5.4-jar-with-dependencies.jar:lib/xmlsec-1.5.5.jar:lib/commons-logging-1.1.1.jar" pl.baczkowicz.mqttspy.Main

openjfx: Installed: 11.0.7+0-2ubuntu2 Candidate: 11.0.7+0-2ubuntu2 Version table: *** 11.0.7+0-2ubuntu2 500 500 http://de.archive.ubuntu.com/ubuntu focal-updates/universe amd64 Packages 100 /var/lib/dpkg/status 11.0.7+0-2ubuntu1 500 500 http://de.archive.ubuntu.com/ubuntu focal/universe amd64 Packages

does not work

error
Error: Could not find or load main class pl.baczkowicz.mqttspy.Main

any idea?