Blank Window opens up - NPE in log (AbstractTableView)

[bflorat]

Reported by aggi on 5 Aug 2008 10:55 UTC After I had to kill the java process as jajuk did not close in time when I had to shutdown my notebook, jajuk is unable to recover. After restarting windows, starting jajuk results in

• 4s nothing happens
• 2s starting up display is shown, progress runs and completes preparation
• window vanishes to be an icon
• no more activity

when I double-click the jajuk icon in the active task bar, the jajuk windows open up with a blank grey panel.

I remove the collection and collection-exit files to let jajuk generate a new library, but this doesn't help.

The logfile shows a NPE as follows:

java.lang.NullPointerException at org.jajuk.base.Item.getDefaultValue(Item.java:202) at org.jajuk.base.Item.getValue(Item.java:145) at org.jajuk.base.Item.getHumanValue(Item.java:367) at org.jajuk.base.File.getHumanValue(File.java:345) at org.jajuk.ui.FilesTableModel.populateModel(FilesTableModel.java:181) at org.jajuk.ui.views.AbstractTableView.applyFilter(AbstractTableView.java:290) at org.jajuk.ui.views.AbstractTableView$1.run(AbstractTableView.java:153)

Additional Note: I created some new attributes for a title and for a genre and saved them. Maybe the bug is located in this new feature?

[bflorat]

Commented by aggi on 5 Aug 2008 10:57 UTC Additional Infos:

• Windows XP Professional
• collection.xml size 7.6 MB
• Java 1.6.0_02

[bflorat]

Commented by bflorat on 5 Aug 2008 15:55 UTC Hum, you're the second person to report this problem. BTW, are you sure you use Jajuk 1.6.2 ? (code lines doesn't match in debug traces and there're no more collection_exit.xml file in 1.6.2), please check the splash screen to get the release as you seem to get it.

On the problem itself :

• I don't think the NPE you provided is the source of this problem. At worse, only a view could be blanck, not the entire screen. BTW, with current 1.6.2, I don't think this exception can be thrown.
• It looks like a dead lock, could you please reproduce the problem and then run the command line jstack -l ?
• Please save your entire .jajuk directory, it can be useful to reproduce the problem later

[bflorat]

Commented by bflorat on 5 Aug 2008 16:14 UTC Updates:

• Sorry, the collection_exit.xml file actually still exist in 1.6.2
• Note that another way to detect deadlocks is to use the 'jconsole' command line -> threads tab -> click on "detect dead lock" button
• When deleting collection.xml and collection_exit.xml files, jajuk should try to load backup files (jajuk-backup-xxx.xml files) and display a popup message like 'loading backup file'. Is it your case ?
• You can get more debug information by setting jajuk.options.log_level=4 in conf.properties file

[bflorat]

Commented by aggi on 7 Aug 2008 14:48 UTC When deleting collection.xml and collection_exit.xml files, jajuk should try to load backup files (jajuk-backup-xxx.xml files) and display a popup message like 'loading backup file'. Is it your case ?

No, it does not load or say anything. It directly goes to icon state. When opening it, the blank window as attached shows up.

I'll try the additional debug actions you recommend and 'll add the data asap.

Regards, Andreas

[bflorat]

Commented by bflorat on 8 Aug 2008 14:36 UTC Hi,

• How did you get screenshot "popup jajuk.JPG" ? did you fix the issue ? (in all cases, please keep a copy of your /.jajuk directory to try to reproduce)
• I still don't understand why your stack traces doesn't match our code. Perhaps an Eclipse issue from our side. Should I assume you downloaded jajuk from http://jajuk.info ? in stand alone version ?

Thanks

[bflorat]

Commented by aggi on 12 Aug 2008 17:40 UTC I created the popup simply by renaming the .jajuk folder, so jajuk starts up as if installed new. To reproduce the issue, I simply rename .jajuk_broken back to .jajuk and the error starts all over again. I do understand that the easiest way would be the put my entire .jajuk folder as zip in here, but I don't like the idea to publish my entire collection.xml. However, I believe I can get you additional info to find out the source of the bug. Maybe I should add that part of my profession is doing quality management for java applications, so I am pretty familiar with bugs, stack traces and the like.

[bflorat]

Commented by aggi on 12 Aug 2008 17:41 UTC I used the win 32 download from jajuk.info for installation.

[bflorat]

Commented by aggi on 12 Aug 2008 17:52 UTC Just an idea: I have multiple JREs running on my machine including eclipse, apache and other web app container. Some of them for sure use other SAX parsers. Isn't there a central registry for parsers in Java? Maybe the JRE assigns the wrong parser to jajuk?

[bflorat]

Commented by aggi on 12 Aug 2008 17:54 UTC Hi bflorat, I added additional log files describing the state. Different versions of XML parser files. Does that give you an idea?

If not, I'll try to reporduce the error by starting with a blank .jajuk. If I remember, I created a DJ, added some attributes to products and categories and renamed some mp3 files using russian and greek charsets.

[bflorat]

Commented by bflorat on 13 Aug 2008 14:33 UTC Replying to aggi:

I created the popup simply by renaming the .jajuk folder, so jajuk starts up as if installed new. To reproduce the issue, I simply rename .jajuk_broken back to .jajuk and the error starts all over again. I do understand that the easiest way would be the put my entire .jajuk folder as zip in here, but I don't like the idea to publish my entire collection.xml. However, I believe I can get you additional info to find out the source of the bug. Maybe I should add that part of my profession is doing quality management for java applications, so I am pretty familiar with bugs, stack traces and the like.

Thanks aggi, I'll check this tonight. In the mean time, a good idea could be to send me directly (bertrand 'at_ florat +dot* net) a zip without the collection files nor the thumb directory but don't feel obliged. Note that it shouldn't contain (almost) any personal information and would probably boost my debug.

[bflorat]

Commented by bflorat on 13 Aug 2008 14:34 UTC Replying to aggi:

Just an idea: I have multiple JREs running on my machine including eclipse, apache and other web app container. Some of them for sure use other SAX parsers. Isn't there a central registry for parsers in Java? Maybe the JRE assigns the wrong parser to jajuk?

I don't think so...

[bflorat]

Commented by bflorat on 14 Aug 2008 07:20 UTC I looked at your logs on DJ and here's my conclusions:

• There's indeed a problem migrating pre-jajuk 1.6 dj. It will be fixed in 1.6.3 (see #1173)
• This problem cannot however explain the blank screen. The problem is elsewhere. I see see two possibilities : * a dead lock caused by a particular situation (please perform the jconsole' command line -> threads tab -> click on "detect dead lock" button test, it takes only few seconds and will make us sure about this point.
  * a corrupted configuration somewhere but I don't see where because jajuk normaly handles any configuration and reset to default in case of problem (like for djs).

[bflorat]

Commented by bflorat on 15 Aug 2008 19:11 UTC OK, after some more studies of your logs, I think we got it.

• On the web radio exception : don't explain how the parse can fail but it cannot cause the problem and right webradio list is downloaded again for internet (if connected)
• The actual problem is apparently that for an unknown reason, your volume has been saved to a negative value (please check it from conf.properties / jajuk.volume entry). We know make a check on it.

Feel free to reopen if you still get the problem with upcoming jajuk 1.6.3.

The fix has been applied against 1.6 branch and trunk.