Here are some further nodes on specifying the class path for jpype.
A. Check JDK path
I had several versions of Java JDK installed and getDefaultJVMPath did not yield the expected path. I needed to replace
jpype.getDefaultJVMPath()
with the path to the JDK, that actually has been used to compile the code, e.g
D:/jdk11/bin/server/jvm.dll
B. relative paths
It is possible to use relative paths. If my python file is for example in a package folder "pkg" and my java class file is in a sub folder "foo" of a "bin" folder:
parentFolder
For this example, the working directory of the java application will be the pkg folder. With other words, inside a main method of Foo class, you might want to use "../" to access the parentFolder.
C. -cp option does not work
I tried to use -cp option instead of -Djava.class.path, which I would found more induitive. However, the following code does not work:
jpype.startJVM(jvmPath, '-cp', classPath)
D. jars need to be included individually
I tried to include a folder with several jar files.
parentFolder
Following code does not work:
jpype.startJVM(jvmPath, '-Djava.class.path=../lib/*")
link = jpype.JClass('foo.Foo')
Each jar file needs to be included individually, e.g.:
libOath = '../lib'
libJarPaths = str.join(';', [libPath + '/' + name for name in os.listdir(libPath)])
jpype.startJVM(jvmPath, '-Djava.class.path=../lib/*")
link = jpype.JClass('foo.Foo')
(Solution from JPype (Python): importing folder of jar's )