Mac OS El Capitan never opens .jar files - java

Every time I try to save a.jar file for my programming course and it doesn't open, and yes I save the META.MF whit the correct path, I even stop making them on the Terminal and use Net Beans but same problem Error: Could not find or load main class a3t8e1.A3T8e1 maybe I need to download something else.
I search on the internet and download the jar launcher but nothing better.
this is the .jar unpacked

Please try to right click the .jar file and click the Get Info. Under the Open with, select the Jar Launcher.app. After that, try to reopen your related .jar file.

Related

Cannot read from an runnable Jar file

I'm trying to make a mp3 player and I used javazoom libraries. I save mp3 path in library.txt file to reopen them. There is not any problem with openning library.txt which is in the jar file.
Normally with eclipse program It is working well but when i created a jar file the problems begins.
I can't use absolute paths to open any mp3 file with my jar file.
File file = new File("/Users/orcungumus/Music/iTunes/iTunes Media/Music/Bruno Mars/Unorthodox Jukebox/1-16 16 Locked Out of Heaven.mp3");
try {
player.open(file);
} catch (BasicPlayerException e1) {
JOptionPane.showMessageDialog(null, e1.toString(),
"Error", JOptionPane.INFORMATION_MESSAGE);
}
For making thinks easier to understand i used directly path of an file. It works for eclipse, but with jar file it can't open file.
This is the error which i take:
If it is important i use mac os.
Edit: I realized that this is not about absolute path by making mp3 path relative. Libraries give an error about audio format. So, the problem is still exist. what can be the differencies between runnable jar file version and eclipse run for an project.
well, that's hard to find out.
now your problem is unable to open a audio file, which I can't handle.
However you said that the programme run perfectly using eclipse, so the question became
the different between running in eclipse and normal jar file.
FIRST, eclipse not directly use java.exe nor javaw.exe for execution. Instead, eclipse use some custom defined library in order to redirect the console, handling exception, etc.
(That is nothing to your problem)
SECOND, eclipse will set the working directory for you automatically (to the project root directory), where may contain some necessary native library.
THIRD, eclipse also define some path for native location for library, I think you may use eclipse built-in export to create the jar file which however not include the native library.
the second and third difference may help you, because they are quite effective to jar file.
I have just browsed javazoom briefly, I don't know whether there is native library. If not,
I sorry that you have to find other solution.

Java App unexpected behavior when exported

I have a very strange problem, that I can't figure out, the thing is that my aplication runs perfectly on the IDE (Eclipse), but not when exported, when I run the jar (double click) the aplication start but some functionality is missing (loading from a template file, but this does not happend when loading from a normal file), when I try to run it from console (java - jar my.jar) in order to see any error message it turns out that my aplication works perfectly fine! :S ...
Some more info:
My app is running over windows 7
I start the task manager, and I noticed that when I start my aplication using double click its under the name java.exe *32, and when I do it from command line its under the name java.exe (without "*32"), as far as I know I programmed nothing related to a 32 or 64 bits functionallity.
"Solved"
Well I was not able to solve it the way I wanted, as far as I was able to find, i found that there were a problem between the 2 java versions I was running x32 & x64, I deleted the 32 bit version and it start working as a charm, but I'm still not sure about what happend, I give my thanks to #Sajal Dutta one of its comments help me to understand part of the problem, thanks to all of you anyway, I'll keep searching until I find the problem...
When you create a jar from Eclipse, your assets don't get copied over to jar or location is not preserved. Open the jar and check if you have your templates in the right location or you have it at all.
To have the exported jar include your assets/resources-
Right click on your project in Eclipse. Then New -> Source Folder.
Name the source folder anything. e.g. template_src.
Copy or drag the entire directory of your template to template_src. Then make the jar.
Since it works via the command line but not when double-clicking the jar, it is likely that the working directory is different (and that you're loading the template with a relative path). When you run an executable jar by double-clicking, on some operating systems, the working directory is the home directory whereas when you run from the command line, it's the directory you're currently in.
The "files" in the jar are not handled by File, but are resources;
URL url = getClass().getResource("...");
InputStream in = getClass().getResourceAsStream("...");
Then, the file paths inside a jar, or on a non-Windows platform are case-sensitive.
"Template_A.xml"
is not
"template_a.xml"
Also you might inspect the jar with 7zip or WinZip.

Cannot open Eclipse after opening once? (Error included)

After opening Eclipse once and without updating, it does not open again. It spits out the error "The Eclipse executable launcher was unable to locate its companion shared library." and does not open. I have Windows and used 7-Zip to unzip the file (I have read that windows default unzip tool corrupts the file). I would like to emphasize that it works once and without updating, but then if closed, will not open again. Thanks for any answers.
That's a very weird behavior.
The The Eclipse executable launcher was unable to locate its companion shared library error popup does indeed happen when you don't expand the archive according to Windows' bizarre requirements, and it seems you've documented yourself well enough before posting this.
I would advise:
erasing the eclipse folder
copying the downloaded archive to a "safe" folder like "My Documents"
right-clicking the archive there, and "extract here"
moving the extracted folder back to its location (32-bit or 64-bit
Program Files)
trying to launch again

Eclipse create java executable with external libraries

I've seen this topic in this forum but it I need a more basic explanation on how to do this.
I've done a program in Java with some external libraries (LWJGL and Slick).
So this is what I've done and my program won't start anyway, tell me where I've done wrong.
I have Eclipse 3.7.1
My project is opened in Eclipse and runs well in Eclipse
I click File -> Export
I select Java -> Runnable JAR file
Here I don't know what to choose in Launch configuration, when I click the dropdown I get the option to choose my main class so I do that.
I select an export destination
I select the option "Package required libraries into generated JAR" under Library Handling
I don't know what ANT script is so I don't use that
I click Finish
I copy my images-folder to the same location as the generate JAR-file
I try to start the JAR-file, something loads in the background but nothing happens, no window shows up, nothing.
I check the Task manager in windows and sees that a javaw.exe is running
What did I miss?
My program uses images for graphics like this:
image = new Image("images/filname.png");
I wonder if I need to change the paths before exporting or the method to load these?
Thanks!
If you want to get things from inside a jar file you need to have them in your classpath and access them as resources.
The constructor you use, refers to a physical file which cannot peek inside a jar-file.
(EDIT) Also note that you have no guarantee where the current working directory is. Hence any relative references may break, as you see.
Read this to learn how to use JarSplice to export your Eclipse project to a runnable jar-file. Regarding images, you can put them in the same directory as a class file (in the jar) and then writeSampleClass.class.getResourceAsStream("image.png")to retrieve an InputStream of the image. Then you can load it however you like.
I had the same problem and I was able to fix it. All I did was copy the data folder (which contains my resources) into the *.jar file. You can do this for example with WinRAR.

Java .jar "Open With" Windows Explorer continually spawns Explorer processes

Wondering if anyone can tell me why trying to open a .jar file with Win7 Explorer ("Open With" C:\Windows\explorer.exe) would cause the computer to continually create (over 200+ in a couple seconds) explorer processes?
Thanks!
Maybe do you want to view the contents of the jar? Take a look to this page. Or try with what is written on this page if you want to execute the jar without the command shell.
EDIT:
The problem of windows explorer is described in this page and in this too.
I'm wondering why you are trying to open a jar file using Windows Explorer...change the properties...set it to run with java.exe....everything should be fine...and coming to the 200+ question...unless it is a virus or something, it should not behave in such a way...strange to see that happen....try opening other jars in a similar way...you'll get to know the problem and the eventual solution...
Had the same problem with opening JAR files.
From here(thanks Alberto Solano):https://social.technet.microsoft.com/Forums/windows/en-US/9237ca68-645c-4718-9a51-24788f312c4b/windows-7-hangs-when-opening-a-file-with-explorerexe?forum=w7itproperf
This works(thanks MVied):
Run Registry Editor
Browse to \HKEY_USERS\S-1-5-21-(random numbers with dashes)\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts(whatever file extension is broken, i.e. '.jpg')\
Delete the folder called 'UserChoice'

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