4.3.1 fails to build on Slackware-14.2/x86_64

[rs-aesi]

I'm configuring a new desktop running Slackware-14.2/x86_64. The jdks
available are openjdk-8u171_b11 and openjdk7-7u181_b01. This is the result
when I try to load the application:

]$ java -jar JabRef-4.3.1.jar Exception in thread "main" java.lang.UnsupportedClassVersionError: org/jabref/JabRefMain :
Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:808)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:442)
at java.net.URLClassLoader.access$100(URLClassLoader.java:64)
at java.net.URLClassLoader$1.run(URLClassLoader.java:354)
at java.net.URLClassLoader$1.run(URLClassLoader.java:348)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:347)
at java.lang.ClassLoader.loadClass(ClassLoader.java:430)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:323)
at java.lang.ClassLoader.loadClass(ClassLoader.java:363)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)

What might be causing this?

[Siedlerchr]

The error indicates that the Java version or the Java home path environnement variable is not set correctly. You need jdk 8 and openjfx 8.

[rs-aesi]

On Fri, 16 Nov 2018, Christoph wrote: The error indicates that the Java version or the Java home path environnement variable is not set correctly. You need jdk 8 and openjfx 8.

Christoph, Installed on that host are jdk-8u191, openjdk-8u171_b11, and openjdk7-7u181_b01. I've not ever installed openjfx and JabRef through version 3.8.2 have worked fine on my 32-bit desktop. There is no explicit java path set in ~/.bash_profile. Rich

[Siedlerchr]

Well, you need openjfx for JabRef >4.x and the error indicates that java 7 is still in the path somewhere or the default java.
Check the version output if you run java -version in the terminal
Try to change the java version with:

sudo update-alternatives --config java 
sudo update-alternatives --config javac 

That should be sufficient. As jdk7 is out of date since a long time you should uninstall that.

[rs-aesi]

On Fri, 16 Nov 2018, Christoph wrote: Well, you need `openjfx` for JabRef >4.x and the error indicates that java 7 is still in the path somewhere or the default java.

Christoph, Okay. I'll install it; there's a SlackBuilds.org package for it. There might be a java application here that still depends on java7. I'll uninstall it, and only build it if an application complains.

Check the version output if you run` java -version` in the terminal Try to change the java version with: ``` sudo update-alternatives --config java sudo update-alternatives --config javac ```

No update-alternatives on Slackware. Regards, Rich

[rs-aesi]

On Fri, 16 Nov 2018, Christoph wrote: Well, you need `openjfx` for JabRef >4.x and the error indicates that java 7 is still in the path somewhere or the default java. Check the version output if you run` java -version` in the terminal

Christoph, I removed the jdk packages and installed openjdk(7) because it's a prerequisite for openjdk8 (at least on Slackware) and openjfk which mates with openjdk8. Although I expected this to allow JabRef-4.3.1 to load it didn't: Installed packages: openjdk-7u181-x86_64-1_SBo openjdk8-8u181-x86_64-1_SBo openjfx-8u60-x86_64-1_SBo $ JabRef Exception in thread "main" java.lang.UnsupportedClassVersionError: org/jabref/JabRefMain : Unsupported major.minor version 52.0 at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:808) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:442) at java.net.URLClassLoader.access$100(URLClassLoader.java:64) at java.net.URLClassLoader$1.run(URLClassLoader.java:354) at java.net.URLClassLoader$1.run(URLClassLoader.java:348) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:347) at java.lang.ClassLoader.loadClass(ClassLoader.java:430) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:323) at java.lang.ClassLoader.loadClass(ClassLoader.java:363) at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482) Please point me to what is still missing here. I appreciate your assistance and look forward to getting JabRef working on the new desktop. Best regards, Rich

[Siedlerchr]

Maybe this article helps you https://medium.com/@swhp/installed-java-development-kit-jdk-on-slackware-14-2-ea133da179d0
Try to locate where the jdk 8 is installed and set the path variable to point to it.
It's described in the article. Afterwards check if the correct version is printed out

[rs-aesi]

On Sun, 18 Nov 2018, Christoph wrote: Maybe this article helps you ***@***.***/installed-java-development-kit-jdk-on-slackware-14-2-ea133da179d0 Try t

Christoph, Unfortunately, it doesn't have the solution. When I try to invoke JabRef I get this error: $ JabRef Error: Could not find or load main class org.jabref.JabRefMain Installed on this host are: $ java -version openjdk version "1.8.0_181" OpenJDK Runtime Environment (IcedTea 3.9.0) (linux-gnu build 1.8.0_181-b13) OpenJDK 64-Bit Server VM (build 25.181-b13, mixed mode) $ javac -version javac 1.8.0_181 openjfx-8u60 Are there other tests I can run to identify the source of the problem? Regards, Rich

[Siedlerchr]

Closing this issue due to inactivity 💤
Please reopen the issue with additional information if the problem persists.