I close my application by pressing a "Close" button. But in the Eclipse I see a red square indicating that something is still running. When I press this red square, I kill my application completely.
Is it possible to find out what is still running (which method, which loop) using Eclipse?
P.S. I am a newbie. So, it would be nice to have a simple solution. I also might not understand your answer if you use "technical" words which I do not know.
ADDED:
I cannot use System.exit since it will kill not only my software but also an "external" software which calls my software.
Have a look at jps and jstack commands they will give you the process id for your application and then you can view the threads and their states using jstack.
Its very useful for this kind of issue.
Sorry just realised you wanted something in eclipse to do this. well I'll leave this answer as it should work but not inside eclipse.
Debug View shows just that. To see the concrete methods for each thread you need to stop the application. Most probably you just need to set default close operation for the main JFrame.
Related
I'm recently working with Eclipse Che and have the task to import a Java Project that opens a GUI in it (like a simple Swing/SWT Calculator).
I am using the Java CentOS Stack, importing the .jar files, etc. is no problem but I get the "No X11 DISPLAY variable was set, but this program performed an operation which requires it." error.
Obviously, I found many threads about that Error, but I just wanted to ask if it is even possible to open a GUI in a web based IDE like Eclipse Che before wasting hours trying to fix that error when it's not even possible.
Maybe some of you already tried that and have a solution/tip or smth for me.
edit: found a video that answered my question. https://www.youtube.com/watch?v=AjgSp0dkxxU
Thanks anyway.
This will help you out - https://eclipse-che.readme.io/docs/che-and-swing
You need to use the right stack
You need to set the display variable. The way I did this was modify the run command to set it just before the other commands.
The command I used is:
export DISPLAY=:0.0
Also note that this worked for a while for me but randomly stop working a few days back so please tell if you manage to get it working.
"Debugception!"
You may notice that within the first 15 seconds of this YouTube video (from 1:01:01 to 1:01:16), Markus Persson (aka "Notch", creator of Minecraft) has somehow managed to save/update an application and attach a debugger to it while it was already under the process of being debugged, supposedly all with a simple keyboard shortcut. The previously coded application somehow magically became the newly edited one, and seemingly without relaunching it or spawning a new process... It's possible that this is just some form of locally remote debugging, but something about it just doesn't seem quite right.
I've spent several days Googling and asking around on how he was able to do this, yet to no avail. I've found no such option under Eclipse preferences, and whenever I try to save & debug an already running application, it simply launches a separate instance of the newly updated application, side-by-side with the older, outdated one.
Am I missing something? How was this possible?
How was he able to utilize such an astounding, powerful debugging feature?
Thanks in advance!
Update
Okay, so this appears to be a standard feature specific to Eclipse.
Coming from a background in NetBeans and Visual Studio, I'm astounded that this doesn't seem to exist elsewhere (or at least in NetBeans!)...
This is a built-in feature of Eclipse. If you edit a method while the program is running in debug mode, it will compile the new method, and replace the old method with the new version. If some thread was already running that method, it will jump back to the beginning (AFAIK; this might only happen when the program is paused).
You don't need to re-launch the program or set any special preferences. Just edit and save, and the magic will happen.
Eclipse can't always figure out how to merge your changes into the running program - usually if you changed anything outside a method body (including the method's parameters or return type). In this case, you will get a warning dialog, with the option to stop the program, restart the program or ignore the changes.
I'm currently writing a pretty large program that calls the same methods from different places.
Now I would really like to see how the program goes from one method to another as it is running. Like a live view that shows when what method is opened (and why?). Call Hierarchy doesn't suit my needs at this point. Is there a way?
One way to follow the logic of your application is by placing breakpoints at the line of code you want your application to stop at but, to do this you'll have to setup it up in debug mode.
Every major IDE will let you do this, including Eclipse.
Have a look at this tutorial:
Java Debugging with Eclipse
Once you setup your program in debug mode you can add a breakpoint in the gutter next to the line numbers.
Sorry in advance. This is a really vague question because I have no idea whatsoever what is going on. I have a Java Swing GUI desktop app that I wrote in NetBeans. While inside of NetBeans, the app works fine and passes all of the tests that I have thrown at it. I've been developing this app over the past several months, deploying it at various phases of its development.
Yesterday, I finished adding and testing some new functionality. I built the application and put it on another computer. I then went to run the program (outside of NetBeans) straight from the jar file. While in the new areas (JDialog boxes), the program crashes. Since I am not in an IDE, I have no feedback to see what is wrong.
The only thing that I can think of (and this is lame) is that I added some switch statements that switch on strings, which I know to new to 1.7. I was previously developing in 1.6. Otherwise, I can think of no reason that the program should work flawlessly inside the IDE, but crash outside of it.
Can anyone offer any suggestions for how I should approach this? I'm at a complete loss.
Thanks very much.
The next debugging step for you is reducing the size of your program until it doesn't crash, then seeing what change you made worked. That should either make the answer obvious or give you a good question to post on SO.
Your idea that it might have to do with switch statements tells you to try:
removing them
removing and compiling on JDK 6 and see if it works
Those are reasonable ways to reduce your program size to see if you can make it run.
I would start from collecting a crash dump data.
If you run the UI on windows you could use DrWatson
If you run the UI in Linux , By default the heap dump is created in a file called java_pidpid.hprof in the working directory of the VM. unless you specify the path yourself by adding this -XX:HeapDumpPath= option to your UI java options.
I want to clear the console output of the NetBeans console. We can clear it manually by using Ctrl+L.
Is it possible to do this programmatically, in Java?
Thank you very much
I think that it's not so simple.
The Netbeans console is not really a full system console.
I'd see a proper option - like getting the console reference using the Netbeans RPC binding, but your application would need to run as a Netbeans plugin or bundle. (so - don't do that, keep it simple)
For a shortcut (workaround) - you may try to use java.awt.Robot class to send a keyRelease event (Ctrl+L) while being focused in the console (effectively sending the Ctrl+L event to the focused component)
This is a poor solution because it doesn't actually clear anything, but it does push it out of the way to hopefully make it more readable.
System.out.print("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n");
add or subtract "\n" to lengthen or shorten it depending on the size of the console window.