I am trying to create my own custom Knime extension. I have istalled the SDK and created an example node that runs in my eclipse dev environment.
When I try to export my node, either through update site or dropin, it is listed as installed in Knime but does not show up in the node repository.
If i run knime from the console I can see an error message stating:
“Caused by: java.lang.UnsupportedClassVersionError: org/knime/example/ExampleNodeNodeFactory has been compiled by a more recent version of the Java Runtime (class file version 66.0), this version of the Java Runtime only recognizes class file versions up to 61.0”
I have two jdks installed on my computer. 17 and 22. I used 22 to compile the plugin because if I use 17 the ant script that comes with the knime-sdk throws an error.
KNIME AP currently requires java 17 and will not yet work with newer java versions. Your error message indicates that you used a java 22 sdk (Class File Versions - javaalmanac.io). You need to set the execution environment to JavaSE-17 to ensure the compiling JDK creates the right bytecode:
I recommend you to use maven to build your extension, it is much more robust than using the update site building mechanism from eclipse directly.
Please take a look at this template repository on how to do this:
Should the methodology in the quickstart guide (Create a New Java based KNIME Extension) work in theory? Or is it outdated and I better start with this Maven repo you linked? I have everything set up according to the quickstart guide and it would be nice to use that setup if possible.
