QtJambi example not executing

Question

I'm trying to compile and run the tooltip code from this tutorial. I obtained QtJambi from my package manager (the package is qtjambi-beta from AUR), which installed it into the directory /opt/qtjambi-beta/. In particular, the qtjambi-4.7.0.jar file is located at /opt/qtjambi-beta/qtjambi-linux64-community-4.7.0/qtjambi-4.7.0.jar.

Now, I made a folder called qtpractice and put the example in there under the name JambiApp.java. The code I put into it was exactly as follows (following the example I linked):

package qtpractice;

import com.trolltech.qt.gui.QApplication;
import com.trolltech.qt.gui.QWidget;

public class JambiApp extends QWidget {

     public JambiApp() {
        setWindowTitle("Tooltip");
        setToolTip("This is QWidget");
        resize(250, 150);
        move(300, 300);
        show();
    }


    public static void main(String args[]){
        QApplication.initialize(args);
        new JambiApp();
        QApplication.exec();
    }
}

I compiled it with javac qtpractice/*.java -cp /opt/qtjambi-beta/qtjambi-linux64-community-4.7.0/qtjambi-4.7.0.jar, which worked fine. I then tried to execute it with java qtpractice.JambiApp, and I got the following error:

Error: Could not find or load main class qtpractice.JambiApp

EDIT: Based on some advice from the comments, I tried this command instead: java -cp /opt/qtjambi-beta/qtjambi-linux64-community-4.7.0/qtjambi-4.7.0.jar qtpractice.JambiApp. When I did this, I got the following error again:

Error: Could not find or load main class qtpractice.JambiApp

What did I miss? From what I can tell, I did everything necessary to make it execute.

You need to give same `-cp` args to `java` command too. That’s common Java practice. — Smar, Sep 30 '14 at 08:09
Please add the whole command line and error to your question. — Smar, Sep 30 '14 at 08:14
You need to add the native jar to execution command too (it’s not required for compilation). — Smar, Sep 30 '14 at 08:26
There should be jar which name is `qtjambi-native-linux64-gcc-4.8.6.jar` or similar, or something with `linux32` `linux64`, depending of how old that version is. Could you give name of that jar so I could make proper answer? :) — Smar, Sep 30 '14 at 08:40
Okay, answered. Sorry for late response, I was at work and forgot about the question :) I hope the thing worked for you though. — Smar, Sep 30 '14 at 15:03

Smar · Accepted Answer · 2014-10-01T11:17:24.217

1

You need to include all jars Qt Jambi needs in classpath.

This can be done on CLI with command similar to

java -cp /opt/qtjambi-beta/qtjambi-linux64-community-4.7.0/qtjambi-4.7.0.jar:/opt/qtjambi-beta/qtjambi-linux64-community-4.7.0/qtjambi-linux64-gcc-4.7.0.jar:. qtpractice.JambiApp

When compiling, native jar does not need to be present, as the native libraries are just for Jambi classes to be able to use Qt.

edited Oct 01 '14 at 11:17

answered Sep 30 '14 at 15:02

Smar

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Also a further note - I tried doing this in Eclipse, and it worked fine. However, I don't really want to use an IDE (and I don't get how it does all this stuff anyway), and this has me really mystified, so I'd like to figure out what the hell is going on. – Koz Ross Oct 01 '14 at 00:20
Well, then give the full error (what the command returned when you ran it) – Smar Oct 01 '14 at 07:28
``Error: Could not find or load main class qtpractice.JambiApp`` – Koz Ross Oct 01 '14 at 08:08
that’s *all* it returned? – Smar Oct 01 '14 at 10:37
I'm as mystified as you are. – Koz Ross Oct 01 '14 at 10:50
Ohh... I think I got it. When you’re running with classpath, current directory is not in classpath by default. So if the class you’re running the file from current directory, you need to add :. to end of the classpath. I’ll update the answer. – Smar Oct 01 '14 at 11:17

QtJambi example not executing

1 Answers1