When executing JAR, get ExceptionInInitializerError: version.properties not found

Question

I've been writing a small project in Eclipse which runs perfectly within the IDE. Then I've build a runnable .jar file through Eclipse (which should include every dependency library inside the jar itself).

I use 3 library in my project:

• derby.jar
• qtjambi-4.7.1.jar
• qtjambi-win32-msvc2008-4.7.1.jar

Then I use this command (in windows):

java -jar prova.jar

And I get this:

Connected to database

Exception in thread "main" java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoa
der.java:58)
Caused by: java.lang.ExceptionInInitializerError: version.properties not found!
    at com.trolltech.qt.Utilities.<clinit>(Unknown Source)
    at com.trolltech.qt.QtJambi_LibraryInitializer.<clinit>(Unknown Source)
    at com.trolltech.qt.QtJambiObject.<clinit>(Unknown Source)
    at WAAAGH.main(WAAAGH.java:52)
    ... 5 more

As you can see the derby.jar is working as expected ("Connected to database"), but there's an error with Qt-Jambi that I can't understand. Any idea?

EDIT: WAAAGH is the class containing the main method, line 52 consists in:

QApplication.initialize(args);

Answer 1

FWIW the location of version.properties has recently been changed to be inside the package namespace of the bundles com/trolltech/qt/version.properties. The old location was a poor design choice and that has now been corrected. The issue is that if you have another JAR in your classpath that also has a toplevel file then the ClassLoader is entitled to think that the JAR with that file is authorative for the package and it does not need to search another JAR for the file. A package is a minimum deployable unit in Java, only specialist ClassLoaders (such as those use in OSGi) have features to work around this part of the Java design.

Usually your toplevel (application JAR) will be first in the list and I bet in that JAR you have one or more files like /log4j.properties /commons-logging.properties etc... it is because one or more file exists it then masks (hides) the file in the qtjambi-X.Y.Z.jar from being seen at runtime. Which is why the problem might not exist when you test a certain scenario but then appear when you try another (when you changed ClassPath in some way).

My commit to the project at http://qt.gitorious.org/qt-jambi/qtjambi-community/commit/f18ce5da3e30b43424bf94e49adf8c4cac0d9862 better explains in code the very recent change to make life better.

It should never have been the case that you have to copy the version.properties file from the QtJambi redistributable JARs into some other part of the Class Path (like the toplevel project prova.jar in your case) this is a bug that has been corrected for the next release. It is the long term intention to remove the need for the file completely and I am 80% there with that goal, as part of that work making multiple native JARs co-exist in the same Class Path will greatly simplify deployment and getting started guides; as well as making them play with OSGi and Eclipse nicely out-the-box.

However no releases have been made yet to include this change but I am very close (within 30 days of doing so for Qt 4.7.4).

Open Source plug alert: Please consider joining the mailing list at http://lists.qt.nokia.com/pipermail/qt-jambi-interest/ from http://lists.qt.nokia.com/mailman/listinfo for announcements.

Answer 2

How is QtJambiObject getting loaded? Have you packeged it inside your prova.jar? The missing file version.properties should be part of the same jar at top level (not in any subdir). It seems you have not packaged it inside prova.jar at top level. See this for explanation of how it is loaded.

You might be better off specifying all jars and main class on command line:

java -classpath prova.jar;derby.jar;qtjambi-4.7.1.jar;qtjambi-win32-msvc2008-4.7.1.jar <your main class>

replace ; with : if you are running on *nix