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run executeable jar with a linux script

I wrote a little java program and now I want to execute this .jar file from a .sh script.
my script:
#! /bin/bash
java -jar /var/spool/sms/sentSMS.jar
then i run the command: sudo bash sentSMS.sh
an get following error:
ERROR: Unable to access jarfile /var/spool/sms/sentSMS.jar
I am using a Raspberry with raspian-jessie, if this important to solve it.
Sorry, but I'm new in scripting with linux.

Take into account that the user must have at least READ permissions on that file.
Also, as you say you are new in linux, make sure the name is correct. sentSMS.jar is different from sentsms.jar

How to find out the command for one java running process?

I'd like to know how it is started. What is the command to start this java process ? What I mean is I have one running java process, and I'd like to know the command to start it, such as what is the main class and what is the arguments, etc.
Any tool for that ? Thanks

There is a command line tool that comes with the JDK: jps, that will give you the list of java processes being run at the moment you execute the command, the arguments given to the method main and the parameters used for the JVM. Try this:
path\to\jdk\bin\jps -m -l -v
It won't give you the exact command used to start the process, but it will give you a hint of how to "rebuild" that command.
For more info, if you are on a decent distro of linux, try man jps or if you are on Windows, see the Oracle documentation about jps.

Your question wasn't clear. If you are looking to find the command that launched this process than you can look at the property sun.java.command. This will give you the main class name and arguments passed to it. java.class.path property gives you the class path. You can get the arguments passed to the java command itself by using ManagementFactory.getRuntimeMXBean().getInputArguments() method. Using all these you should be able to reconstruct the java command.

If you use Windows, you can use the Taskmanager, go to the Process/Details Tab, where you can see the PID for each Process. There you can add a column for the command line (e.g. in German its "Befehlszeile", i'm not sure how that column is labeled in English).
Then just look at the java.exe/javaw.exe Processes.
You could also use the alternative Taskmanager from Microsoft, Process Explorer, afaik there you can just click right on a process and select details.

Launch Java with a specific argument each time

I have a program which allows me to define the java executable (/usr/bin/java), but does not allow me to add specific arguments to the executable.
I want to be able to run Java with a specific argument each time in order to enable Security Manager.
So far, I have tried to add the argument after /usr/bin/java, so it looks like
java=/usr/bin/java -Djava.security.manager -Djava.security.policy=/home/java.policy
That did not work as the program probably checks to see if a file exists. Another way I tried was to make a bash script called java which contained:
/usr/bin/java -Djava.security.manager -Djava.security.policy=/home/java.policy $*
I then set the java path to /home/java (Location of my script). That however did not work either. Is there some sort of way I can do this?
Thanks.

Put your java call in a shell script java.sh:
#!/bin/bash
/usr/bin/java -Djava.security.manager -Djava.security.policy=/home/java.policy $#
Change permissions with chmod u+x java.sh, then call your program with java=./java.sh (adapt path for your script as needed).
Notes about executable bit and shebang line
Both the shebang line (#!/bin/bash) and execute permission are important here. Without them, system calls of the exec* family will fail because the kernel does not know what to do with the file or because execution is rejected due to the missing executable bit.
This is different when run directly from a shell (./java.sh), because most shells have some compatibility feature for that case so they will run a script in a shell if exec* fails. The execute permission must be set though.
The only case where neither is needed is if you give your script as argument to the shell: bash java.sh.

Your second approach would be ok, but your problem is likely to be that your Multicraft application is not finding your script. More so, it's the environment of your web server (Apache?) that may need to have PATH altered to be able to find your java wrapper script.

Java runtime exec

I am trying to do something using system exec in Java
Runtime.getRuntime().exec(command);
Surprisingly everything that is related with paths, directories and files is not working well
I don't get why and just want to know is there any alternatives?

The alternative is to use the ProcessBuilder class, which has a somewhat cleaner interface, but your main problem is probably related to how the OS processes command lines, and there isn't much Java can do to help you with that.

As noted above, cd is a shell builtin. i.e. it's not an executable. You can determine this using:
$ which cd
cd: shell built-in command
As it's not a standalone executable, Runtime.exec() won't be able to do anything with it.
You may be better off writing a shell script to do the shell-specific stuff (e.g. change the working directory) and then simply execute that shell script using Runtime.exec(). You can set PATH variables etc. within your script and leave Java to simply execute your script.
One thing that catches people out is that you have to consume your script's stdout/stderr (even if you throw it away). If you don't do this properly your process will likely block. See this SO answer for more details.

The exec() method can take three arguments. The third is the directory your subprocess should use as its working directory. That solves your "cd" problem, anyway.

Shell script: How to put absolute path into command?

I was trying to execute my java program through shell script so I wrote:
java -jar $(pwd)"/test.jar"
It worked flawlessly but when I turned to the code below:
PATH=$(pwd)"/test.jar"'
java -jar $PATH
Then I got an error: "Run.sh: 3: java: not found"
(Running on Ubuntu)
I have very little experience in shell script so please let me know what's wrong with it. Thanks.

PATH is a special environment variable which the shell uses to find executables. You've changed PATH to point at test.jar, so now the shell can't find java.
Call your variable something else.
Example:
LIB_PATH="$(pwd)/test.jar"
java -jar ${LIB_PATH}

The value in $(PWD) depends on the directory the script is called from (print working directory). If you call the script from another directory, than the one your jar-files resides in, you'll get the wrong path. And you changed the search path of the SHELL, that will prevent the shell from finding any other binary e.g. java.

PATH is system-reserved variable, that define the way where your system should look to find the executable (in your case java). Therefore you shouldn't use it in your code as variable to your test.jar .
In my opinion, your code should be something like:
#!/bin/sh
PROGPATH='/path/to/your/test.jar'
JAVAEXEC=`which java`
JAVAPARAMS='-j'
GLOBALPATH="$JAVAEXEC $JAVAPARAMS $PROGPATH"
echo $GLOBALPATH