Add .dll to java.library.path in Eclipse/PyDev Jython project
Asked 07 September, 2021
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I'm trying to use a compiled .jar Java library in my PyDev Jython project.

I successfully added the .jar to the PYTHONPATH and was able to begin coding with auto complete working.

The library requires a .dll extension as well, javaHeclib.dll, so I added that to the External Libs section of my project.

I can import the library fine, but I get an error when I try to access any of its functions:

java.lang.UnsatisfiedLinkError: java.lang.UnsatisfiedLinkError: no javaHeclib in java.library.path

I added a VM argument to my Run Configuration, with no luck:

-Djava.library.path="Y:/path/to/javaHeclib.dll;${env_var:PATH}"

I can run the library from the command line just fine using the java.library.path above.

Experimenting in the PyDev Console, I noticed I can load the .dll extension with an absolute path, but not a relative one:

>>> import java.lang
>>> java.lang.System.load('Y:/path/to/javaHeclib.dll')
>>> java.lang.System.loadLibrary('javaHeclib')
Traceback (most recent call last):
  File "<console>", line 1, in ?
java.lang.UnsatisfiedLinkError: java.lang.UnsatisfiedLinkError: no javaHeclib in java.library.path

Unfortunately, the library is using the the System.loadLibrary call above, and I don't have access to its source.

Why is javaHeclib.dll not in my java.library.path?

EDIT

Setting the java.library.path to the directory containing the dll didn't allow me to load it using System.loadLibrary.

-Djava.library.path="Y:/path/to/dll/;${env_var:PATH}"

(Using forward slashes didn't make a difference.) I also tried changing the default VM args in eclipse.ini, with no luck:

-vmargs
-Dosgi.requiredJavaVersion=1.5
-Xms40m
-Xmx384m
-Djava.library.path="Y:path	odll;${env_var:PATH}"

3 Answer