Loading JDBC connector in Eclipse Jython plugin - eclipse

Question

I'm working with an Eclipse-based tool which provides an interactive Jython shell for scripting and data analysis against an internal data model.
I'm trying to write a script which exports results to some form of database, so I'm trying to use the built-in com.ziclix.python.sql package in Jython to provide the interface and the Xerial JDBC connector for SQLite (https://github.com/xerial/sqlite-jdbc) to provide the backend.
The script below works perfectly when run outside of the third-party tool using a standard command line Jython interpreter, including relying on the importJar() hack which is commonly used to work around Jython not always using the user CLASSPATH when run using java -jar <blah>:
from com.ziclix.python.sql import zxJDBC
from java.net import URL, URLClassLoader
from java.lang import ClassLoader
from java.io import File
JDBC_URL = "jdbc:sqlite:test.db"
JDBC_DRIVER = "org.sqlite.JDBC"
JDBC_JAR = "E:/sqlite-jdbc-3.21.0.jar"
# Import Jar file into local class path
def importJar(jarFile):
m = URLClassLoader.getDeclaredMethod("addURL", [URL])
m.accessible = 1
m.invoke(ClassLoader.getSystemClassLoader(), [File(jarFile).toURL()])
def main():
try:
importJar(JDBC_JAR)
dbConn = zxJDBC.connect(JDBC_URL, None, None, JDBC_DRIVER)
cursor = dbConn.cursor()
# Do something useful
cursor.close()
dbConn.close()
except zxJDBC.DatabaseError, msg:
print msg
if __name__ == '__main__':
main()
... but fails when run from the plugin inside Eclipse, where the zxJDBC.connect() call errors with:
driver [org.sqlite.JDBC] not found
If I add the Jar file to the JYTHONPATH environment I can do import org.sqlite.JDBC successfully in the Python script, but the connect call still fails in the Java-side of the JDBC driver manager.
For sake of completeness the full path to the Jar file is on the CLASSPATH, PYTHONPATH, and JYTHONPATH environment variables ...
Any ideas?