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I have a java project, which I converted into jar file. And later, my C# project is using that jar file with this code

proc = new Process();
            proc.StartInfo.WorkingDirectory = jarDir;
            Console.WriteLine("\nDirectory with jar file is\n" + jarDir);
            proc.StartInfo.FileName = jarName;
            Console.WriteLine("\npassed arguments are" + ifs_id.ToString() + " " + max_record.ToString() + " " + max_time.ToString() +
                " " + outputName + " " + outputDir);
            proc.StartInfo.Arguments = " " + ifs_id.ToString() + " " + max_record.ToString() + " " + max_time.ToString() +
                " " + outputName + " " + outputDir;
            proc.EnableRaisingEvents = true;
            proc.Exited += new EventHandler(OnProcessExit);
            proc.Start();

And all was working prefectly. Problem begins when I transfered my project to other computer, also working under windows10. It dosent work. Process starts, and imidiately finishies. Whats more, I cant run jar file by double clicking on it, and I think that this might be the case. When developing code, everything works perfectly. But when i converted project to .jar file, it stops working.

Its not a problem with directories, I double checked them.

I have no ideas what my be causing this situation. I will realy appretiate any advices.

Mateusz Boruch
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2 Answers2

1

Check the following:

  1. Does the .jar file which your program calls reside on the computer that you moved the program to? You can't use that Process class if you need to access the .jar file from a remote server.

  2. When you say it "stops working" does it throw an error at all?

  3. Did you check if java is installed on the computer that you moved the program to (run java -version in command line)?

ferris
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  • .jar file is definietly on the computer, this file is part of C# project, and its added to project directory. It's not throwing anything. After .jar file finishies its job, it should create a .csv files with resoults. When I ran java project i receive such file. When i convert java project to .jar file, and double click on .jar file i receive nothing in return. The same happens when i run .jar file from c# project. Just nothing happens. And java is 100% intalled on second PC. I even moved all java IDE to second computer to debug it here. And still, java project works, but .jar doesnt. – Mateusz Boruch Oct 10 '19 at 18:28
  • @MateuszBoruch - ok, well what displays when you run java -version in the command line? Also, instead of double clicking, if you run the jar file as: java -jar JarFilename.jar what results do you get? – ferris Oct 10 '19 at 18:47
1

Your code: proc.StartInfo.FileName = jarName; tells Windows to run the .jar file with whatever it has associated as a handler for jarfiles. It is the same as double clicking.

So the fact that both methods don't run means the Java runtime on Windows isn't a registered handler to the jarfile. Depending on the JRE flavours you have installed, most of the Open JRE installers don't do it. AdoptOpenJDK has started including the jarfile handling option into the installer i think some time this year(?).

Option 1

Fix the jar file association. This should make it work on your other computer, but you would need to do it on every other computer that are having the same issue.

On the bright side, this will also fix double-clicking on the jar, something that Option 2 below doesn't do.

You have a few options to do this:

  • Use a JRE/JDK installer that does it for you (e.g. AdoptOpenJDK's installer).
  • Do it manually. This particular answer (not the one marked as accepted) should work.
  • If you're not against running a third-party tool made by a random stranger on the internet, jarfix would automate the manual way above.

Option 2

Make your program trigger Java even if it's not currently associated with jarfiles. This will likely make it run on more computers, but won't fix your jar double-click issue.

This requires Java to already be installed and is in your OS's PATH. To test this, fire up a command prompt, and run java -version. If you get a response, keep reading. If you don't, you need to look up how to include Java in your PATH.

Now, in your StartInfo, you want to call java and not your jarfile directly:

proc.StartInfo.FileName = "java";

You then specify your jar as part of the argument:

proc.StartInfo.Arguments = " -jar " + jarName + " " + ...the rest of your args.

You can replace "java" with "javaw" if you know you'll only ever run it on Windows.

NPras
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  • Thank you for your help. It was indeed problem with association but diferent one. One of libraries included to java project was not corectly added to .jar file. On my first PC it worked, becasue jdk could find those libraries on my PC because it was compiled and created there, and those libraries were added to environmental variables. On second PC it didnt work, becasue those libs was not included in environmental variables. Now, I added those libs when creating jar files, but they didnt add finaly, because of bad file name(-.-). .Jar file was created, but without association to this lib. – Mateusz Boruch Oct 11 '19 at 14:42
  • Finaly I renamed those libs, and they added properly as association to jar file and everything works perfectly again. I even tested it on two more PCs and its working. – Mateusz Boruch Oct 11 '19 at 14:44
  • It was also a reason why it worked while compiling in IntelliJ. Because that lib was added as reference there. But it failed in .jar file, because it failed to add this lib. Nonetheless it was your suggestion that helped me find it out, so again, much thanks :) – Mateusz Boruch Oct 11 '19 at 14:47