Develop Reference

Ansible issue when trying to execute java command from playbook

I'm in the middle of automating some processes in a VM, we are currently using java 17 and have updated out jettys to jetty-11. Since in jetty-11 both home and base are separate it's important to initialize the jetty-base folder. I need to do it from ansible
I worked out a solution in local shell but trying that in ansible it's not working
- name: "Run initialization command"
shell: "nohup java -jar '{{ jetty_home }}'/start.jar jetty.base='{{ jetty_install_dir }}' --add-module=server,http,deploy,annotations,logging-jetty,jsp &"
There are no obvious errors when I run the playbook, just
TASK [jetty-distribution : initialize jetty-base] **************************************************************************************************************************
changed: [****************************] (cutting the vm name off)
Is there any solutions to this issue ? Thanks in advance

You most definately should be using 2 separate directories.
(repeated here for others that see this question in the future)
The jetty.home directory.
This is for the jetty distribution (or the more modern jetty-home tarball/zip).
The jetty.home directory is sacred, don't edit/change/remove/add/modify ANYTHING in this directory. You don't need to, for any possible configuration you can come up with (trust me).
The jetty.base directory.
This is the directory for your configuration, or instance of Jetty.
Make sure this directory does not nest inside/outside of the jetty.home directory, you'll just make your life needless complicated when it's time to upgrade (or even downgrade) your Jetty version.
Next, when it comes to initialization, turn off nuhup, that just hides any errors you might have during initialization. The --add-module command is terminal anyway and will do what it needs and then exit, it's not a daemon and keeps running. If you don't want to see the output, at least redirect it to an output file you can interrogate if there's issues.
Don't put it in the background either (the & at the end), the exit code will be useful to you if an error occurs.
aka
java -jar /path/to/jetty-home/start.jar \
jetty.home=/path/to/jetty-home \
jetty.base=/path/to/my-jetty-base \
--add-module=http,deploy,annotations,logging-jetty,jsp \
2>&1 > /path/to/my-jetty-base/jetty-init.log
Keep in mind that some modules, when added, require user interaction (to accept licenses). This can be handled in scripts by using the --approve-all-licenses option on start.jar.
Lastly, are you sure ansible supports the "Jakarta Big Bang" namespace changes that Jetty 11 implements?
See past answer on this: https://stackoverflow.com/a/66368511/775715
If ansible has updated to Jakarta EE 9, then go ahead and use Jetty 11, if they haven't, then stick with Jetty 10 (which is on Jakarta EE 8) until such time that ansible catches up with the rest of the world.

How to execute Carrot2 Document Clustering server

I downloaded the Carrot2 Document clustering server build 3.15.0 for Mac. The read me file says:
The DCS requires a Java Runtime Environment (JRE) version 1.7.0 or later. To
run the DCS, execute the 'dcs' script and point your browser at
http://localhost:8080 for further instructions.
Mac OS Sierra doesn't make it easy, but I got 1.8.0_112 installed.
The problem is that I don't know how to execute the 'dcs' script.
There are .cmd, .sh, .war, and .jar files. I wasn't sure which of those to work with. I thought .jar looked promising, so I followed some of this thread and tried this in a terminal window:
java -jar invoker.jar
I cd-ed to the correct directory, but it just says Provide main class, but I'm not sure what or where that is.
Can anybody provide instructions or a link to how to do this?

Use the dcs.sh (on Linux/Mac) and dcs.cmd (on Windows) to start the server. The scripts will set some extra options for the JVM and then start the DCS. In case of any problems, append the -v option to see diagnostic output.

How to run .jar continually and automatically on Debian server?

I have a .jar file I want to run all the time on a Debian server.
Currently I have figured out how to access the server via ssh on Cygwin and start the .jar. But when I close the Cygwin window on my development machine, it kills the process on the server (I think, as it's not responding any longer).
Currently I start it like this:
java -jar myjar.jar packageName.fileNameOfFileWithMainMethod
I need to make this file run automatically and continually on the server (it is an integral part of the system I am developing).
Unfortunately I know next to nothing about server management, or non-windows operating systems in general (wasn't me who chose or made the server), so I really don't know what to do, nor what to search for (apparently, since my searching gave no usable results).
I have read (and edited because the text was a mess) this question, but although I feel it might be hinting in the right direction, I didn't get much help from it. I also tried my best googlefu, but it got me a lot of only tangentially related results.
I guess I'll have to make some kind of script (possibly containing the code line above), do some stuff to it and put it somewhere specific on the server to accomplish what I want to do.
Would someone be so kind as to explain how this is done?

Shell hooks are good for configuring user environment variables.
Cron is for scheduled jobs, mostly related maintenance, such as creating backups, managing log-files etc ...
Background processes with nohup as advised by Николай Митропольский, or ssh with "screen" application (which let you detach/reattach to a "session"), will be useful in development time.
But can not handle server shutdown cleanups, or respond to restarts.
Init scripts mentioned above is the standard way to start/stop services.
There is an application named init, which is the first application started when a Unix-like system boots.
Init, according to runlevel, starts some scripts, and those scripts manages daemons (services in Windows).
So for services, you write "hooks" for runlevels,
In Debian, /etc/init.d/ where you put your init scripts,
you can read the scripts inside this folder to get the idea,
they are text files (bash scripts).
Those scripts are called with an argument
(a standard keywords, such as "start", "stop" etc..).
/etc/rc?.d/ (where ? is one of runlevels), where the init finds the scripts to run.
But those scripts are just "automatically created" symbolic links to the scripts in /etc/init.d/.
You do not need to touch anything inside /etc/rc?.d/ folder.
*After putting your script into /etc/init.d/,
you only need to call to create symbolic links *:
sudo update-rc.d "your-scripts-name" defaults
As you see there are some prefixes attached to names of scripts;
for example /etc/rc1.d/K10apache2 which is a symbolic link to /etc/init.d/apache2.
So a simple "ordered by name execution" is possible here.
Automatically creating those prefixes (so the execution order),
dependency information is required.
So init scripts includes this information.
Also information required when (at which runlevel) those scripts should be called (with "start" or "stop").
This dependency information is placed as comments in those scripts.
Forexample apache server init script (/etc/init.d/apache2) includes those lines;
# Provides: apache2
# Required-Start: $local_fs $remote_fs $network $syslog $named
# Required-Stop: $local_fs $remote_fs $network $syslog $named
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
Detailed information exists in Debian policy;
https://www.debian.org/doc/debian-policy/ch-opersys.html#s-sysvinit
also this will be usefull;
https://refspecs.linuxbase.org/LSB_2.1.0/LSB-generic/LSB-generic/iniscrptfunc.html
NOTE:
There is a huge transition and debates/fragmentations in Unix world.
Init and init scripts, tradationally used in Unix/Unix-like systems, nowadays becoming obsolete on many systems.
https://en.wikipedia.org/wiki/Init#Replacements_for_init
Debian currently uses systemd, but init scripts still works with systemd (systemd provides the compatibility).

One simple suggestion would be to run the jar file using Linux's CRON.
This article from unix stack exchange should get you going the correct direction for running a jar file using cron.
Alternatively, this article from mkyong.com is also clear and concise.
For example:
Connect using Cygwin
Run crontab -e
Enter 0 * * * * java -jar myjar.jar packageName.fileNameOfFileWithMainMethod to run the jar file every hour at the top of the hour. Or, to start it once on server startup enter #reboot java -jar myjar.jar packageName.fileNameOfFileWithMainMethod

Simplest solution is to detach process by using nohup with &:
nohup java -jar myjar.jar packageName.fileNameOfFileWithMainMethod &
to stop process will be possible with kill <process-id> command
process id could be found by ps -ef | grep packageName.fileNameOfFileWithMainMethod
But if you are developing serious application that is long-running on server you have to deal with initialization system like systemd, upstart or something like that.

Using Bumblee (Graphics Drivers) with Eclipse IDE [duplicate]

Does anyone know how to make eclipse or netbeans use the graphics card in optimus laptops by invoking optirun (bumblebee) inside the IDE so that one can just use the run button in the IDE to run the program in a graphics card within the IDE.
In simplest form I just want the IDE to do the equivalent of optirun ./javaproject

The way I did this in Eclipse was to first start the Java debugger jdwp and listen to a port. Then start the JVM with optirun java ... and use jdwp to connect to this port. Both tasks can be started at the same time in Eclipse by creating a Launch Group in the debug configuration settings (Run -> Debug Configurations). In detail:
Create a Remote Java Application debug configuration with "Standard (Socket Listen)" Connection Type and some arbitrary port, e.g. 56789. This attaches the Java debugger jdwp on port 56789 to a virtual machine which accepts debug connections at this port.
Now we need to start a JVM with optirun. This can be done with a External Tool Configuration (Run -> External Tools -> External Tool Configurations). Create a new Program configuration in the left side of the External Tools Configurations window. You could directly start optirun java <additional arguments> by filling in the required fields. However, I have decided to use a shell script which is reusable by different projects (As can be seen below, there is one part missing to make it entirely reusable. I'm glad for any help from more experienced Eclipse users...). Hence, the Location field points to this shell script. The script itself accepts three arguments: the classpath for the project, the name of the Java executable, and the port number. These arguments can be passed to the script in the Arguments field of the Main tab, e.g.
${project_classpath:${selected_resource_name}}
ExecName
56789
The shell script looks like this, assuming optirun is in your PATH:
#!/bin/sh
CLASS_PATH=${1}
JAVA_EXECUTABLE=${2}
PORT=${3}
# TODO: fix this java library path: pass it as an argument as well. Is there an Eclipse variable which stores this?
JAVA_LIBRARY_PATH=/usr/local/share/OpenCV/java
#------------------------------------------------------------------------------
optirun ${JAVA_BIN} -agentlib:jdwp=transport=dt_socket,suspend=y,address=localhost:${PORT} -Djava.library.path=${JAVA_LIBRARY_PATH} -Dfile.encoding=UTF-8 -classpath ${CLASS_PATH} ${JAVA_EXECUTABLE}
#------------------------------------------------------------------------------
Finally, the two pieces are brought together in a Launch Group in the Debug Configurations window (Run -> Debug Configurations). Create a new Launch Group and add the two previously generated Debug configurations by clicking on Add in the Launches tab and by selecting the appropriate configurations.
Note that due to the classpath variable in step 2 (i.e. ${project_classpath:${selected_resource_name}}), the appropriate package needs to be selected in the Package Explorer before clicking on the run debug configuration button (make sure that the Launch Group is selected).
This solution works perfectly for me: I can debug Java code inside Eclipse which calls native code involving CUDA optimizations and Bumblebee only activates the discrete graphics card when necessary.

Just use optirun to start the IDE. For example, optirun eclipse or optirun netbeans

I build the project in Netbeans (F11) and run the following in a terminal:
optirun java -jar path/to/javaproject/dist/javaproject.jar
Mind that if you have any java parameters in your project, you need to add it manually. My workflow is like this:
Locate the Java options from the project, open Project -> Properties, Run. At VM Options I see -Djava.library.path=lwjgl/native/windows;:lwjgl/native/linux. I also have some parameters that I want to pass to main(String[]). With this information, I open a terminal and run:
cd path/to/javaproject
optirun java -Djava.library.path=lwjgl/native/windows;:lwjgl/native/linux \
-jar dist/javaproject.jar some paremeters
Another hint, if you have to open and close the program frequently, run optirun bash in a different tab so that preparing the use of the graphics card becomes faster. Alternatively, you can run optirun netbeans, but that means that the nvidia card will always be on even if you are programming which increases power use and increase the heat.
Important: if you are using a 32-bit JVM or Java libraries on a 64-bit machine, you also need to install the 32-bit drivers and libraries. For Ubuntu, the nvidia package already contains 32-bit drivers, see this answer. For other distros, you likely need to install lib32-* packages for Mesa, VirtualGL and nvidia-utils.

You can also rename java to java_real and use this portion of code as your java command :
#!/bin/bash
path=$(dirname $(readlink -f $0))
args=""
runner="$path/java_real"
for var in "$#"
do
if [ "$var" = "-3d" ]; then
runner="primusrun $runner"
else
args="$args $var"
fi
done
$runner $args
NOTE : I had to do this in /usr/lib/jvm/java-7-openjdk-amd64/jre/bin, not in /usr/bin to make it work with Eclipse.
In Eclipse, just add "-3d" in your program arguments and you're good to go !

using javaw to run jars in batch files results in more than one java processes in process explorer - XYNTService

I have a somewhat strange issue. I have a java application that installs few services that run as Jars. Previously I used installed Java to run these Jars. There are four services and all will be instantiated from a single batch file with sequential call to each other. Something like this,
start %JAVA_HOME% commandtoruntjarfile
would work and all four services will run in the background and only one java.exe visible in process explorer. So I had another service installed as windows service which would start stop these services by calling the run bat or shutdown bat.
Now the customer requirement changed to using an internalized version of java. I extract java to a location, make our own environment variable name "ABC_HOME" and the required syntax in batch changes to
%ABC_HOME%\javaw commandtorunjarfile
When its run it works. but there is no stopping these. When I go to process explorer I see 4 java.exe running each for the four run commands in the batch file. If I stop the windows service all the four keep working. If I restart the windows service the number of java.exe in process explorer goes to eight and keeps going up until windows has had enough of it.
How do I get around it? I think the solution should be to have the one java process in process explorer but I cant seem to find any solution for that.
[EDIT]
The four sub services are actually XYNT processes. In the normal scenario it would be something like this
[Process1]
CommandLine = java -Xrs -DasService=yes -cp jarfiles
WorkingDir = c: bin scache
PauseStart = 1000
PauseEnd = 1000
UserInterface = No
Restart = Yes
For using java from a specific location the following change was needed
CommandLine = %JAVA_PATH%\bin\java.exe -Xrs -DasService=yes -cp jarfiles
but this wouldn't work as it would not accept the path variable in XYNT.ini file. so I called a batch file here and in that batch file I used the above code. So here is what the change looks like,
CommandLine = batchfile.bat
and in batchfile.bat
%JAVA_PATH%\bin\java.exe -Xrs -DasService=yes -cp jarfiles

Usually, every Java program run on your system has its own virtual machine running, which means: one java.exe/javaw.exe per instance of your program.
I can not tell why it "worked" from your point of view with java.exe like you described first, but the behaviour you described for javaw.exe (having 4 java processes in the process explorer) would be what I'd have expected.
For me the question is not why you're seeing 4 vs. 1 java processes, but how you can start/stop the "services". Killing the Java VM externally doesn't seem a very good solution. I'd consider building some IPC into the Java services that allow you to gracefully terminate the processes.