node-java java.import not working with a packaged electron app

Cross reporting the issue reported in node-java https://github.com/joeferner/node-java/issues/352

With a package app using an asar archive, java.import does not work. The following line of code will throw an error:

var DateTime = java.import('org.joda.time.DateTime');

Error: Could not create class org.joda.time.DateTime
java.lang.NoClassDefFoundError: org/joda/time/DateTime
Caused by: java.lang.ClassNotFoundException: org.joda.time.DateTime
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

    at Error (native)
    at Java.java.import (...)

Only the packaged version of the app fails. Launching the unpackaged electron app will work fine.

The app was packaged with the following command:

electron-packager ./app --out=dist --asar.unpack='**/node_modules/java/**/*'

I guess the function java.import needs to be adapted in order to work with packaged electron apps.

Let me know if I can provide more information.

regards

[kevinsawicki]

@antoinepairet I think the issue is that the internal classpath paths in node-java need to be using the asar.unpacked directory instead of the app.asar one. https://github.com/joeferner/node-java/blob/126bfa821cefcb8af21e323990d9985936938a97/lib/nodeJavaBridge.js#L23-L31

I got it working with the following patch to your repo:

diff --git a/renderer.js b/renderer.js
index c2997dc..9744f4b 100644
--- a/renderer.js
+++ b/renderer.js
@@ -3,10 +3,18 @@
 // All of the Node.js APIs are available in this process.

 'use strict';
-const java = require('java');
+
+const path = require('path');
+
+let java
+if (path.extname(__dirname) === '.asar') {
+  java = require('../app.asar.unpacked/node_modules/java');
+} else {
+  java = require('java');
+}

 var list1 = java.newInstanceSync("java.util.ArrayList");
 console.log(list1.sizeSync()); // 0
 list1.addSync('item1');

-module.exports = list1.sizeSync();
\ No newline at end of file
+module.exports = list1.sizeSync();

[gpinkham]

@antoinepairet I know this is a really old issue but curious. how did that code work for you? building the electron app with webpack ends up including both requires (it doesn’t run the if statement). Did you use some other packer? thanks!!