-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Arun,
Arun Raj Ramkumar wrote: | Can you tell me the impact of using following commands in a java program in | tomcat? Yikes! Spawning processes can be dangerous business on a production system. Be VERY careful what you do, here. | Will they take more memory? They will take whatever memory is required of them. However, they do not directly take memory away from the JVM. Of course, you will need to use of the JVM resources to track the Process as it runs (and hopefully completes). | Will they take time to release memory? Generally, the OS will reclaim any memory used by a process as soon as it terminates. Remember: the process must terminate, and there are certain things that can keep the process around (such as not reading the stdout and stderr streams from Java -- BE CAREFUL!). | Is there any other way we can call? My preferred methos for these types of things is: 1. Store data somewhere central (an RDBMS or the filesystem) and run a batch job. This divorces job execution from the servlet container, and tends to be safer and more stable. Of course, if you have any kind of immediate-response requirements or are expecting synchronous execution, this is not possible. 2. Have the "outside" program run as a deamon, and communicate via TCP/IP. Process management is soooo much more of a pain in the heck than communicating via a socket (although socket connections require more API work for the programmer). | to find best way | print statments on the child perl will affect the parent tomcat? Just remember that you have to read 100% of the output and error streams of the child process, or your child process might never die. This is really bad if you have lots of calls to these processes. You can easily get an OOME from "too many files open" because each Process gets at least 3 file handles allocated to it. | Invoking perl programs like the following ways: | | 1) Process process = new ProcessBuilder(params).start(); | process.waitFor(); | | 2) Runtime.getRuntime().exec(command+" &"); | | 3) RunCommand runcmd = new RunCommand(cmd); | runcmd.start(); Yeah, this is the naive way of executing a process. You need to manage all the streams, too, or you can run into trouble. There are several libraries that exist to help you run external processes without having to do everything yourself. One such library is commons-exec (http://commons.apache.org/exec/). Check that out and see if you can get that to work. The API is probably just as simple as what you're doing, but I think it will be a lot safer -- if you decide that spawning child processes really is the best thing to do. Hope that helps, - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkhoQZsACgkQ9CaO5/Lv0PALOwCdEvgvpcephqvFcCGI8edm0umP Y0YAn0qZwt0mJjt22jlPavtrUJqyKNMn =M32n -----END PGP SIGNATURE----- --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
