jep.JepException: <class 'ImportError'>: math.log

[mwxiaomao]

Describe the problem
A clear and concise description of what the problem is.

Environment (please complete the following information):

• OS Platform, Distribution, and Version: mac 10.12
• Python Distribution and Version: 3.7.9
• Java Distribution and Version: 1.8.0_251-b08
• Jep Version: 4.2.0
• Python packages used (e.g. numpy, pandas, tensorflow): No

Java code:
try (Jep jep = new SubInterpreter()) {
jep.eval("import math");
jep.eval("result = math.log(10)");
double result = jep.getValue("result", Double.class);
System.out.println("Natural logarithm of 10 is: " + result);
} catch (JepException e) {
e.printStackTrace();
}

jep.JepException: <class 'ImportError'>: math.log
at /Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/jep/java_import_hook.getattr(java_import_hook.py:57)
at .(:1)
at jep.Jep.eval(Native Method)
at jep.Jep.eval(Jep.java:326)
at com.my.cloud.JepTest.main(JepTest.java:30)
Caused by: java.lang.ClassNotFoundException: math.log
at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
... 3 more

[ndjensen]

The ClassNotFoundException in the stacktrace indicates it's trying to import math.log as if it was a Java class. You presumably have a Java package on your classpath starting with math. Jep uses a ClassEnquirer to decide if it should attempt an import from Java or Python. You will need to implement a custom ClassEnquirer that indicates correctly if the package should be imported from Java or Python. The default ClassEnquirer, ClassList, takes all the Java packages on the classpath and indicates those should be imported from Java, which is why I believe you have a package starting with math on your classpath.

For related issues, discussion, and examples, see #173, #377, #466.

[mwxiaomao]

Thanks