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Editorial Team
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Asked: 2026-06-06T18:31:09+00:00

I am a total newbie in JSPs/Tomcat and to a large extent in Java

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I am a total newbie in JSPs/Tomcat and to a large extent in Java as well. Here’s what I have to do — when a user clicks a button/visits a URL, I want to launch a Java program (which takes some command line arguments).

I can very easily do 

Runtime.exec("C:\\Python27\\python.exe test.py")

OR 

Runtime.exec("java -cp %CLASSPATH%;C:\\devprojects HelloWorld"

and this works fine. Where HelloWorld.class just prints “HelloWorld”.

However, when I attempt a java program which takes command line arguments, the GET request just hangs doing nothing. I don’t know what logs to look for or what could be wrong here. After having spent TWO days on trying various things, I am just about to give up now.

Runtime.exec("java -cp %CLASSPATH%;C:\\devprojects Run --username Blah --password Foo");

What user does Tomcat end up running this java program as? Can I make it to be Administrator? This is on Windows 2008, does UAC interfere with things?

I cannot modify the Run.class here, I HAVE to run it as is and with command line parameters.

Please advise.

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1 Answer

  1. Editorial Team

    One idea: you are relying on the default tokenization of your command line as one complete String, and it is not parsing the last one as you expect. Instead you should use the form of this method that takes a String[], after you have chopped up the command line yourself:

    http://docs.oracle.com/javase/6/docs/api/java/lang/Runtime.html#exec(java.lang.String%5B%5D)

    Or, it is waiting for input from you, or waiting for you to read its output. This could explain the hang. Search the internet for the dangers of streams and Runtime.exec().

    Consider ProcessBuilder instead.

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