Jython won't import user-defined class; ImportError: No module named ******

Question

I\'ve been banging my head against the wall for a couple days now trying to figure this out. I\'ve been starting to play around with Jython for fast prototyping. I\'ve hit w

Answer 1

I think there may be an error in that example. When you import X in Jython, this looks for a Java package named X, not for a class named X.

Try:

// Beach.java
package com.stackoverflow.beach;

public class Beach {
    private String name;
    ...

and in Jython:

from com.stackoverflow.beach import Beach
bondi = Beach("Bondi Beach", "Sydney")

edit: Also, you might want to make sure that the full name of the .jar file -- and not just the directory where it resides -- is listed on the CLASSPATH. This is certainly necessary in Java, and I assume Jython's rules are the same in this regard.

Answer 2

jython can't import *.java file you need to compile it to *.class.

Makefile:

.PHONY: test_beach

test_beach: test_beach.py beach.jar
    jython -J-classpath beach.jar $<

beach.jar: Beach.class
    jar -cf $@ $<

%.class: %.java
    javac $<

Example

$ make -k 
javac Beach.java
jar -cf beach.jar Beach.class
jython test_beach.py
*sys-package-mgr*: processing modified jar, '/path/to/beach.jar'
Cocoa Beach

Other files

test_beach.py:

#!/usr/bin/env jython
import Beach

beach = Beach("Cocoa Beach","Cocoa Beach")
print beach.getName()

Beach.java:

//NOTE: if you declare `package a.b;` here then you should put it in a/b directory
public class Beach {

    private String name;
    private String city;


    public Beach(String name, String city){
        this.name = name;
        this.city = city;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

}