RuntimeError: Can't find org.jpype.jar support library

[IPLCZAT]

With the new release 1.6.0 which was published today on PyPI we are getting this error

File /local_disk0/.ephemeral_nfs/envs/pythonEnv-a6dc78f6-b3ef-4e69-9692-0bb7cf74df10/lib/python3.11/site-packages/jpype/_core.py:357, in 
startJVM(jvmpath, classpath, ignoreUnrecognized, convertStrings, interrupt, *jvmargs)
    355 prior = [locale.getlocale(i) for i in categories]
    356 # Start the JVM
--> 357 _jpype.startup(jvmpath, tuple(jvm_args + extra_jvm_args),
    358                ignoreUnrecognized, convertStrings, interrupt, tmp)
    359 # Collect required resources for operation
    360 initializeResources()

RuntimeError: Can't find org.jpype.jar support library

when running

jpype.startJVM()

It works with 1.5.2

[Mishco]

The same issue, I need to switch back to previous version pip install jpype1==1.5.2

[bh1428]

For me it works (jpype1==1.6.0) when using a 64 bit Coretto JDK21.0.7_6 (on 64 bit Windows Server 2022). However when using a 64 bit JDK1.8.0_162 I'm getting the Can't find org.jpype.jar support library error.

I'm using the same virtual environment: .venv\Lib\site-packages\org.jpype.jar is present in both cases. JDK 1.8 seems not to find it.

[Thrameos]

We dropped support for Java 1.8. The issue is supporting versions pre module support is becoming a bifrication in the jar and tooling.

[edhollandHGV]

FYI this issue impacted a large number of production databricks jobs for my team yesterday. We believe that JayDeBeApi package installed the updated 1.6.0 version of Jpype which in turn lead to the Can't find org.jpype.jar support library error. Downgrading to 1.5.2 solved the issue for us.

[Thrameos]

Yes definitely something we should highlight better in the release notes. Unfortunately Java 1.8 is currently nearly 7 years past the end of it service life of 2019. While Oracle may offer support until 2030, it would be very constraining to be tied to a product from 2014 especially since Java 1.8 and Java 9 are different beasts. Unfortunately that means 1.8 users will need to pin to 1.5.2.

[khaeru]

Just to note for others who may be investigating similar issues:

• We see failures in iiasa/ixmp with the same error message on GitHub Actions jobs that run on the windows-latest (currently windows-2022) runner image.
• As of now the default Java version on these runners is "8.0.452+9".
• Per “Java version history” on Wikipedia, "Java 1.8" is the same as "Java SE 8", so I think this default version is the one for which JPype1 has dropped support.
• We'll try to:
  • Use GitHub's first-party actions/setup-java to force use of the already-installed "11.0.27+6" for these jobs.
  • Advise our users that they should do the same.

Totally understand the decision and no objections to it. Thanks to @Thrameos and the other maintainers!

[marscher]

RuntimeError: Can't find org.jpype.jar support library

I think this exception message is confusing. Could we treat this is in a clearer way?

[Thrameos]

The issue could be resolved if we probe the version. But the location is before we have any resources loaded meaning the most fragile point. We would need to call java.lang.System.getProperty to find the jvm version. Then parse it for version 1.8.

[astrelsky]

The issue could be resolved if we probe the version. But the location is before we have any resources loaded meaning the most fragile point. We would need to call java.lang.System.getProperty to find the jvm version. Then parse it for version 1.8.

Just had an idea. What about grabbing one of the jvm/jdk jars from the jvm_root/lib and probing the class file version? I haven't actually checked but I would assume that the small number of jars that are there would have a version for the current one. You would only need to check that it is not less than the class file version for Java 9.