How to run a jar file multiple times? CentOS - java

I'm hoping someone can tell me how to run a jar file (located on Desktop) multiple times with one command? Ideally without a new terminal window opening for every instance as well. A bash script would be sufficient too, whatever is easiest for yourself.
Currently I'm just running java -jar filename.jar for each new instance but it gets repetative when I need to have 50 or so instances open.

Try this:
for i in {1..50}
do
java -jar filename.jar
done

Related

Java - System.out.println() viewable from application?

I have a Java application that runs great :) While uploading files, it uses the standard output to show progress : "System.out.println(...);".
When I run it in Eclipse, well it works perfectly, but when I run the JAR file, I don't see any console/terminal showing up and printing what I print through "System.out.println(...),".
How can I open a new terminal when my application is launched (it is a Swing application)?
Basically I want to be able to run the Swing application and show information on the side in a terminal / console. Why? Don't worry about why I want to do this ;)
Thanks a lot!
Regards.
Open terminal and run application as java -cp yourjar.jar YouMain or java -jar yourjar.jar if you jar is runnable.
I believe that you do not see output because you are running your application using javaw - the special windows-only variation of JVM that does not have STDOUT at all. If you want to click your application and see output map *.jar file to be opened using java instead of javaw. Alternatively write bat file that runs your application. In this case you will see console.
Use java instead of javaw to launch your application. Double-clicking on a jar executes it with javaw. Instead, open a command line window and type
java -jar thePathOfTheJarFile.jar
If you want to have something double-clickable, then write a shell script containing this command, and double-click the shell script instead of the jar.

Using task scheduler for running java jar (from batch file)

I am scheduling a task (with windows task scheduler) which simply run a batch file.
this batch is running a jar file (Java program) with a simple "Java -jar test.jar".
When i run the script from the command line manually, the java program runs well and no exception is shown.
but when the task schedular does the same (calling the command), the java program ends with an exception: "ClassNotFoundException" for one of the classes which is in my jar.
What way be the cause of this? what is the diffrence when calling the jar from the command line and from the task scheduler?
Thanks.
I reckon that probably the "current directory" is different, and as a consequence java doesn't find the jar at all. In the first line of your .bat, can you do a cd \path\that\you\expect before you execute java?
Does your jar have any dependencies? Also, it'd be helpful to know what's your folder structure, and how exactly do you run it in the command line.
Anyways, depending on your case, you can do something along these lines:
cd /path/to/exec/folder // set current directory
java -cp /all-classpath-jars/and-or-bin-folders/ test.jar your.package.MainClass [args...]
This has to work, if you specify everything you need correctly.

Running a JAVA program as a scheduled task

I am trying to run a simple JAVA program once per day on a Windows 7 machine.
My code runs fine inside NetBeans. If I do a clean and build it suggests this:
C:\Program Files\Java\jdk1.7.0/bin/java -jar "C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\Facebook.jar"
This does not work from the DOS prompt of course because of the space between program and files so I do this:
C:\Program Files\Java\jdk1.7.0/bin/java -jar "C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\Facebook.jar" -jar "C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\Facebook.jar"
This works from the DOS prompt.
I now create a task in Windows Scheduler to run:
C:\Program Files\Java\jdk1.7.0/bin/java
with arguments:
-jar "C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\Facebook.jar"
When I then run it, all I see is a DOS box flashing up for a second. I expect the code to take about 30 secs to run. The code should persist data to a database and no updates happen.
The code also uses java.util.logging so I should see log entries and I don't.
I strongly suspect that I am not running the JAVA command properly or that there's a bad classpath issue that it present when running via Scheduler that isn't there when running from the DOS prompt.
Help would be appreciated. If you've seen this before and can sort it that would be great. If you can tell me how to get a meaningful error trace from Scheduler than that would also be really helpful.
Thanks!
I Think that you could create a simple batch script that will launch your program in this way :
#echo off
REM Eventually change directory to the program directory
cd C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\
REM run the program
"C:\Program Files\Java\jdk1.7.0\bin\java.exe" -jar "C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\Facebook.jar"
Copy it into the notepad and save as java_script.cmd and then schedule this script instead of the program directly.
I solved it after changing all fonts' references to "SansSerif"
I was using Jasper Reports inside Java to create a PDF file. It was working fine when I double click the batch file or Scheduler with Windows Server 2003 but not working with the Scheduler of 2008.
I tried many different things nothing worked so I though Could it be that Windows Server 2008 is blocking the access?.
Now is working perfect. So, if you are having problems check the references to anything you are using.
The scheduler will run under a different user unless you specify what user to run as. If it isn't running as your user then it won't be able to write to your directories.
The real problem to the original question is a java installation issue on Microsoft systems. Java jre installs into Program Files\java. The executable (java.exe) is only installed in that java\bin directory. Running from the command line, the os looks in the proper location for the java.exe. Running from other MS tools (such as VBA Excel or in this case TaskScheduler), it does not!
You can see that TaskScheduler is looking in the wrong place by viewing the tasks history in the TaskScheduler tool. Double click on some of the history events and one will list the action and return code. The action will show that the TaskScheduler is trying to run
"C:\Windows\system32\java.EXE"
So, copy java.exe from the java\bin directory into the place where the scheduler is looking, and now it will work.
Or update your task and provide the full path to java.exe.
You can also update the environment system path to look for java in the java\bin directory, but that has to apply to all users and sometimes this is faulty as well.

Starting Java app from cmd works, from batch not

The Problem is as follows:
I have a Java Application packed in a ".jar"-File.
I can start the App (Swing Application) by either
doubleclick on the jarfile
commandline java -jar MyApp.jar
However when I put the commandline command into a batchfile, it will tell me
Unable to access jarfile MyApp.jar
The batch file is in the same directory as the jar. Just where I also started from cmd-line.
I tried to call the bat with Administrator-rights and from an admin-shell - no effect.
I'm working on a Windows 7 (64bit) machine. Any hints will be appreciated.
EDIT
You asked for it :) Here is the batch file:
#ECHO OFF
java -jar MyApp.jar
#PAUSE
EDIT 2
Invoking the batch by double-click and from cmd has the same effect.
Changing the command to
java -jar "C:\Full\Path\MyApp.jar"
has no effect.
EDIT 3
I added SET Path=%Path%;C:\Path\To\Jar to the batchfile. No effect.
I also tried using double backslashes as suggested by Chris' link and supported by Viruzzo. Also no effect.
When you double click on .bat file, the working directory is not set to where the .bat file is, but is usually something like %AppData%. To make it work you need to put the full path to the file inside the bat (i.e. java -jar C:\path\to\jar\MyApp.jar).
I just had to put my path in quotes, even though it had no spaces or odd characters.
java -jar C:\Users\Jacob\executables\some-file.jar failed, but
java -jar "C:\Users\JStamm\executables\some-file.jar" worked.
This isn't the answer to your specific problem, but this will allow you to troubleshoot the problem so you will find an answer. Adding a sleep command will let the command prompt sit, so it doesn't close right away.
ping 1.1.1.1 -n 1 -w 10000
(sleep for 10 seconds)
Make sure you don't have the hide extension option enabled in windows. Maybe the name of your jar ends with .jar.jar? Are you sure the path to the jar is correct?
I havent't yet figured out why, but now it works:
The first batchfile was a copy of another and I just changed the contents to fit my needs.
NOW I renamed it to MyApp.bak and wrote a new MyApp.bat from scratch.
As soon as I find out, what the difference was, I'll update this answer.
UPDATE
It happened again with another batch. This time, we got the reason: For some reason, the batch file did not inherit rights when copied. Creating a new one in the folder had the correct rights. So, in the end it was indeed a rights-issue.

How do I open a .bat containing a GUI in a java program in Linux?

everyone. I'm quite new here so please be tolerant if I make any mistakes.
I have a .bat file containing a command line to open up a .jar file that contains a program that has a GUI in it. The only line that's in the .bat file is:
java -jar "NewServer.jar"
I've been trying to use Runtime() to get this to run, but most the instructions I find to open a .bat file in a java program are for Windows. I'm currently using Fedora 12 (don't tell me to upgrade, I can't) if that makes a difference and programming using Eclipse. I also found this ProcessBuilder thing, but I couldn't get it to work so unless you have very explicit directions on how to use it, please don't include it in your answer. I would much rather use Runtime. It looked simpler.
Here's my code to test using Runtime in a java program. I'm hoping that if I can get this to work, I can get it to work in my real program.
import java.io.IOException;
public class testbat {
public static void main(String[] args) {
Process proc = null;
try {
proc = Runtime.getRuntime().exec("./ myServer.bat");
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("Cool");
}
The last line is just there for me to see if the program actually ran in case the GUI doesn't open. Also, I've already tried many combinations of things to include in the area after ".exec". I've tried using a path like "~/user/workspace/ProjectServer/dist/myServer.bat" to no avail.
I also already know that .bat files are for windows, but I'm able to execute it in linux, so I don't know if that makes a difference. I also tried using a .sh file the same way and it didn't work.
Please bear in mind that I'm not that great at Java, but I had to use it for this particular program, so if your answers could be really descriptive that would be awesome.
Just take that line out of the bat file, and run it. Yo're making it too hard.
$ java -jar "NewServer.jar"
will work. The quotes aren't necessary, so
$ java -jar NewServer.jar
will work as well. If you want to have the equivalent of your bat file, create a file named, say, run_newserver containing that line. Change its mode to executable:
$ cat > run_newserver
java -jar NewServer.jar
^D
$ chmod a+x run_newserver
$ ./run_newserver
Ideally, since you shouldn't have scripts without comments, do this. In your favorite editor, create a file run_newserver containing
#!/usr/bin/env bash
java -jar NewServer.jar
and chmod that. The line with #! -- often called a "shebang line" -- is UNIX magic that lets you say what interpreter you want. The program env in usr/bin finds your program and runs it (needed because different systems put bash in different directories.)
You could even put explanatory comments in the file too.
I'm a little unclear why you want to use Runtime#exec to run it at all -- it seems you'll just need a shell script to start that program.
Why are you using Java to run a Batch file, that in turn runs a Java program? Why have Batch in the loop at all? Just put the jar in your classpath and call it directly.
Batch (.bat) files are only for Windows environment. So, Try using shell script
Process proc = Runtime.getRuntime().exec("myServer.sh");
Just open up terminal and do this
vi /dir/to/exec/exec.sh
tap "i" and write this
#!/bin/sh
java -jar "NewServer.jar"
or if you want to run it in the background
#!/bin/sh
java -jar "NewServer.jar" & > /tmp/JavaServer.log
hit esc and type ":wq" and you have saved the file.
type this into the terminal
chmod +x /dir/to/exec/exec.sh
this give executable privileges and then you should run the file like
sh /dir/to/exec/exec.sh
Process is only initialized by your first call. You need to run:
proc.waitfor();
to get it to actually run your app.

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