I think I am having a weird problem:
I 've written a small application in java implementing a JTable to display some results.
I am also using the Substance L&F as my "skin".
Everything seems to be working perfectly.
When I upload the app on my server as webstart, strange things start to happen:
At some point my app generates a little JTable. Every time I mouse over that table,
the app's JButtons or menus or any swing control in general will stop responding. My only option is to close the window and restart the application. Note that the interface seems not to be frozen but like it's lost its focus... if I try to click in any of the table's cells, the UI will still be responsive (not on the swing controls though).
If I get rid of Substance, the problem goes off and everything is working normally again.
If I use another "skin" like JTattoo everything works flawlessly as well.
This only happens when I use the webstart. Does anybody know why..?
or better has any hints on how to fix it?
Related
Ok, so this is a really, REALLY weird issue that we're having with the application at my company. I'm going to try and describe this as best I can.
First, this is a legacy application with a Swing UI.
Second, the issue only occurs when it is compiled & run using Java 8. With Java 7 and below, this does not occur.
So, the issue: When a dialog is displayed (modal or non-modal, doesn't matter), the UI becomes unresponsive to mouse clicks. What's truly crazy, though, is the UI is NOT frozen. Hovering the mouse over something produces the hover highlight as normal. Keyboard commands are received perfectly. Mouse clicks, however, do not work.
This also only occurs on OSX. Windows and Linux don't have this problem. I'm running this on OSX El Capitan.
As far as code samples, it's affecting all dialogs across the application. JOptionPanes & JDialogs, doesn't seem to matter. Here's a simple JOptionPane declaration:
int n = JOptionPane.showOptionDialog(mcContext.getMapperView(), "xPath of dropping target can't be evaluated" +
"\nPlease, select xPath for dropped node",
"xPath calculation for dropped node",
JOptionPane.YES_NO_CANCEL_OPTION, JOptionPane.QUESTION_MESSAGE, null, options, options[0]);
This code IS being called on the EventThread, so I don't believe it's a threading issue.
I'm totally stumped as to the cause of this. So far we've ignored it by compiling and running it in Java 7, but at some point as versions progress we will need to deal with this issue more directly.
Anyone have any ideas?
Edit: Thanks for the SSCCE Idea. Now I'm more confused than ever. When I put together a quick frame/dialog demonstration, it worked perfectly. No issues. So I don't know what it is in the application that could be causing this. Any good places to start looking?
Edit 2: Wrapped one of the declarations in SwingUtilities.invokeLater, and it worked. Ok... now what could the culprit be? It's still got to be something that Java 8 is compiling different than Java 7.
Edit 3: More weird behavior. I moved my IDE into a separate "desktop" than the application it was running, and when the buggy dialog is displayed, i cant switch to that desktop. I can switch to any app on the current desktop, but not to another desktop.
Edit 4: The dialogs in question are being triggered by drag and drop actions. Not sure if that helps or not, but I do see that there is a thread in the background in the thread dump using the sun.lwawt.macosx.CDragSourceContextPeer class.
Alright, it took a while, but I think I found it. I found an OpenJDK post that seemed to very clearly describe this issue.
https://bugs.openjdk.java.net/browse/JDK-8139393
Somehow, Drag N Drop in Swing on OSX in java 8 isn't releasing its hold on the MouseEvent or Listener, so when a modal dialog is displayed the mouse isn't able to get new events through to it. Which is a crazy stupid bug, but it's there.
The solution was wrapping my code in SwingUtilities.invokeLater(...). By having the code that displays the dialogs executed asynchronously from the drag and drop code, the drag and drop operation is able to complete and release its hold on the mouse connectivity (for lack of a better description). And viola! Problem solved.
Thanks to everyone who tried to help. Hope this post helps out anyone else dealing with this issue.
I recently tried to open a JPanel form that I created with NetBeans GUI Builder and NetBeans almost freezes up on me. The design form is an all-gray background, not the usual gray area where I can place components surrounded by a white background. If I click on the Source button and then switch back to Design view, all of the tabs in the editor pane disappear.
Fortunately I am using Git for version control. The last commit of this file was over a week ago. I might have to revert to an earlier version to see where this problem was introduced. In the mean time, does anyone have any idea what could cause this behavior? Is it possible that my .form file is corrupted? The application compiles and runs just fine.
It sounds like Netbeans can't load the form due to some internal error. This can sometimes be fixed by doing a clean & build to clear out any old cached data.
If that doesn't work, you can check out the "message.log" for the error...and yes, I wish it would display it on the screen
Off memory it use to be in "{user.profile}/.Netbeans/{version}/var/log" (I think). It got moved on Windows under 7.2 to "{user.profile}\AppData\Roaming\NetBeans\7.2\var\log"
I'm having issues with my Java Swing Applet. I recently reformatted my computer and reinstalled Eclipse to continue work on my application but I'm having an issue when the screen redraws. Up until now the code has worked 100% (No issues) so I'm certain its an issue with my configuration settings.
The Applet will load fine but after any form of event the screen redraws to something like this:
http://i.imgur.com/vODrs.png
I'm using Eclipse Helios with pretty much a bare bones installation. Its configured to use jre6 but I have no idea why this occurs.
**Please also note that if I embed the applet in an html file it works fine! I however need the applet to run for various debug features I need while working on the AI
Verify that you are constructing the GUI on the event dispatch thread. This is required for Swing applets, too.
Probably because you are missing a super,paintComponent(g) somewhere when you do custom painting.
We have a Java Applet built using AWT. This applet lets you select pictures from your hard drive and upload them to a server. The applet includes a scrollable list of pictures, which works fine in Windows, Linux and Mac OS X 10.5. We launch this applet via Java Web Start or within a web page.
Our applet does not behave properly in Mac OS X 10.4, regardless of the version of Java (1.4 or 1.5). You can find a screenshot of the incorrect behaviour, when scrolling, here:
http://www.lavablast.com/tmp/ui_error.png
Simply put, sometimes when scrolling the pictures end up overlapping the header or footer of the application. This behaviour does not occur on other platforms. On Mac OS X 10.4, it shows the pictures in the incorrect location when scrolling, which would not be so bad if it refreshed the screen after painting the image at that location. However, it does not appear that the application knows it painted it incorrectly and thus does not refresh.
If the window is minimized, resized or even moved, the application is refreshed and the incorrectly positioned elements vanish and the application resumes normally. I spent quite some time trying to force a refresh of the background image unsuccessfully. (the repaint the image directly, repaint all children of a few panels, etc. ) Thus, I am looking for any tips that would help me resolve this problem under Mac OS X 10.4 or, in the worst case, simply simulate a full applet refresh.
Until recently, everything was compatible with Java 1.1 but this has changed in a few locations which now require 1.4. I don't feel these changes created the issue, I am just providing this as extra information. If you are interested in implementation details of the scroll panel, I will investigate, but I am assuming this is a common platform bug for which workarounds must be known.
To replicate the problem, open the following Java Web Start application:
http://www.lavablast.com/tmp/opal-webstart.php.jnlp
Select a folder containing lots of images and play with the scrollbar. At some point (fairly quickly), you should get the refresh problem.
Edit: I followed the first suggestion here and replaced all my controls that feature background images with a Swing equivalent and the issue is still there. (Plus, there are numerous other fixes I would need to do to do a complete change). Any other ideas? A simple one line of code that forces a full refresh would be great :)
Edit2: The main thread creates the panels and launches X threads. Using an observer/notifier pattern, the threads complete and notify the main control, which adds a panel to the page. This is done via an EventQueue.invokeLater which, unless I am mistaken, should run on the right thread. The issue is at its most severe when scrolling even if no extra threads are running (as during the loading).
It does look like mixing lightweight (usually Swing) and heavyweight (AWT) components together. Moving to Swing you need to replace every last AWT component Swing equivalents (hint: avoid import java.awt.*).
Threading is often a potential problem for odd bugs. Swing components must always be used on the EDT (use java.awt.EventQueue.invokeLater). AWT is thread-safe is theory, but not in practice - also restrict usage to the EDT.
As you already require Java 1.4 you should consider some small changes to take into use SWING GUI instead, it solved our Applet refresh issues with AWT. (Mac, Linux etc)
If you have e.g. Panel, you need to replace it with JPanel etc.
You need this:
import javax.swing.*;
I want to create a hangman game as an applet, so I have some labels and buttons that will be initialized by the generated code of the gui designer but I also have some labels I create on my own, after knowing how long my word is. Therefore I use absolute layout for my applet.
In netbeans my applet works finde when I run it but when I try to run it in the browser (I tried Firefox and IE) nothing is on the display, the applet is empty.
can someone help me with that?
Here you can find the source if it is helpful
http://root.xelluloid.de/Hedgeman/Hedgeman.java
With kind regards
Sebastian
Did you look at the Java console for the browser? It likely contains something that says that the program crashed because it could not find the AbsoluteLayout class.
This is for an older version of NetBeans, but the same should apply: http://forums.sun.com/thread.jspa?threadID=597783
I just had the same trouble with an applet and AbsoluteLayout and netbeans 7.1.
Everything works fine but errors are thrown when the applet runs from a browser.
I solved this by switching, in the form designer, from AbsoluteLayout to "Free Design" (which seems to default to GroupLayout in the code that is actually generated) but offers similar functionality (widgets can be placed without restrictions, borders, or even on top of others).
You could probably include the AbsoluteLayout Class/jar into your project and continue using this code. But in my case the code can't exceed 32KB and needs to be self contained (single file) as it needs to be uploaded to a small embedded device.