Ubuntu Java: How to run Linux shell scipt from Java program and fetch back its output

Hi: I am using Java (HTTPUnit) in Linux machine. I am using HTTPUnit multi thread to visit a web application (Hibernate, Spring, tomcat, mysql). Experts in this forum give me the script to see Tomcat JVM memory consumption. Now when I use HTTPUnit to visit a page, then I want to check memory usage by the program themself. And see how much memory consumption it takes. If the memory consumption is bigger, I could write it to some file. My question is from Java program how to run a linux script and how to get output back.

The script is as follows: It could be stored in some executable file called checkTomcatJVM.sh.

ps aux | awk '{print $4"\t"$11}' | sort | uniq -c | awk '{print $2" "$1" "$3}' | grep java
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flob9Connect With a Mentor Commented:
Something like this :

Process proc = Runtime.getRuntime().exec(new String[] {"script","param"});

byte[] buff = new byte[1024];

InputStream out = proc.getInputStream();
int nb = out.read(buff);

But, as mentionned before, calling external process for this purpose is quite dirty.
you can use the Runtime class from java to get the total memory and freememory!

check Runtime.freeMemory()
Use ProcessBuilder to execute the external process.
Wait for the process to complete, and capture its output stream.
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Runtime.getRuntime().exec(new String[] {"script","param"});
JianJunShenAuthor Commented:
Runtime.getRuntime().exec(new String[] {"script","param"});

This sounds a good solution to run script. But how to fetch output?
JianJunShenAuthor Commented:
Oh; sorry , I push the wrong button. Now the excellent answer would be closed. My mistake.
JianJunShenAuthor Commented:
Excellent answer and very fast.
you need to read in a loop to ensure you get all output written to stdout

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