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How to faster the execution of shell_exec?

So I have a shell exec command that run a a java command, load a jar file it ask for input then produce an output in the browser. I'm done with the coding and its working just fine, but the problem is its a bit slow. So, is there a way to make it faster? A certain command or something?

Run bash file from java

I want to run bash file from java, i am using play framework.
any idea how to do that??
is this code enough:
new ProcessBuilder("pathToYourShellScript").start();

Possible duplicate of How to run Unix shell script from Java code? (don't have the reputation to put that in a comment, sorry).
In a nutshell - your line of code will work and the shell script will run by just doing that (tested on a SUSE Linux box).
However, if you want to do anything with the output or to know that it has completed, you'll have to add more code to check its state (check out the Process.waitFor() API) or to capture its output in Java (e.g. by capturing Standard out in a BufferedReader) - check Process.getInputStream() API.

Get status report from shell script to java code

Can any one tell me how to get status report from shell script to java code.
Use case : I run a shell script from java code and if I get any error in shell script(while running) then I need to send some message from shell script to my java code.
So how I can acheive that.

I'm sure there is a better way, but an easy way to do this is to have the shell script pipe error output to a file, which you then read by the Java application.

I'm assuming you are using a ProcessBuilder launch your shell script.
Once you build the process you can use getInputStream() which will give you the output stream from the Shell Script, then just copy the stream to where you want to go.
There also is a redirectOutput but I have limited experiences using it. I'm assuming it does what I'm describing above.

You can use something like this:
Process proc = Runtime.getRuntime().exec("ls -la")
// To get the error code (0=success)
int outCode = proc.exitValue()
If you need to send something from the script to the application executing it, you may be able to do that writing to stdErr in the script and using proc.getErrorStream in your java program.

Running .jar file within JSP page

I'm trying to develop a website that takes user input and converts to a text file. The text file is then used as an input for a .jar file. (e.g. java -jar encoder.jar -i text.txt), the jar then outputs a .bin file for the user to download.
This jar is designed to be run from command line and I really don't know the best way to implement it within a .jsp page. I have created a few java test classes but nothing has worked so far.
Does anyone have any suggestions on possible methods?

An alternative to running it as an external process is to invoke its main class in the current JVM:
Extract/open META-INF/MANIFEST.MF of the jar
Identify the Main-Class:. Say it is called EncoderMainClass
Invoke its main method: EncoderMainClass.main("-i", "text.txt")
This aught to be faster because a new OS process does not need to be created, but there may be security considerations.

Have you tried somrthing like this,
Create a java file
use a ProcessBuilder and start a new JVM.
Here is something to get you started:
ProcessBuilder pb = new ProcessBuilder("/path/to/java", "-jar", "your.jar", "thetextfile.txt");
pb.directory(new File("preferred/working/directory"));
Process p = pb.start();
ps: do handle to destroy process else it will eat up all memory

You can put this jar to the web application on the classpath and use it's class and methods. Better if you have javadoc if you don't have sources. But even if not in classpath you can try the example or this example.

Powershell process hanging when called from Java application

I am trying to write a simple application that takes in a command line arguement (which will be a Powershell ps1 file) and then run it. So I have experemented with a number of different approaches and seem to be running into a problem. If I attempt to invoke powershell from within java, the windows process is started and is visible via process explorer, however powershell never returns, it hangs in some sort of loop by the looks of it. The command I am using is:
String command = "powershell -noprofile -noninteractive \"&C:\\new\\tst.ps1\"";
The command is then executed using:
Runtime systemRuntime = Runtime.getRuntime();
Process proc = systemRuntime.exec(command);
At the moment I am hard coding the location to the ps1 file as I was trying to rule this out as an issue. Using a process explorer I can see the hanging powershell process and the command that was passed to it was :
powershell -noprofile -noninteractive "&C:\new\tst.ps1"
which when copied into a cmd window, works to launch the tst.ps1 file. The file itself is incredibly simple in this example and I think I can rule it out being the cause of the freeze as I have tried to launch other ps1 files the same behaviour can be seen.
To further add to the confusion, if I use the java code posted above and pass in powershell commands instead of a file name then it successfully runs.
I've scoured the web and see lots of people experiencing the same issue but no one seems to have posted there solution, I hope its a simple oversight on my part and can be easily fixed.
Any hints/tips are appreciated :D
Alan

You have to close OutputStream in order for Powershell to exit.
Runtime systemRuntime = Runtime.getRuntime();
Process proc = systemRuntime.exec(command);
proc.getOutputStream().close();

Is your external program writing to the standard outputs (err and out)?
If yes, it can hang waiting for you to consume them from the java parent process.
You can get those as InputStreams by calling
Process.getInputStream()
and
Process.getErrorStream()
There's more details here:
Javadoc for Process