4

I plan to spawn a child to do some work. I want to spawn the child using the same command line as the parent process.

For example, if the parent was started like so: 

#>/usr/bin/java ParentProgram

then I would call 

Runtime.exec("/usr/bin/java ChildProgram");

Example 2: 

#>/usr/bin/jdb -cp ./:/home/name/tool/library.jar -Xmx4G ParentProgram

then I would call 

Runtime.exec("/usr/bin/jdb -cp ./:/home/name/tool/library.jar -Xmx4G ChildProgram");

I know that I can find the classpath from the System properties. And instead of using Runtime.exec I plan to use ProcessBuilder, which copies the environment of the parent to the child's environment. But basically I want to use the same java program and arguments as the parent gets. I haven't found this information in the System properties.

TejasInstrument
  • 41
  • 1
  • 2
    Seems to be answered here: http://stackoverflow.com/questions/1518213/read-java-jvm-startup-parameters-eg-xmx – aioobe Nov 23 '10 at 21:31
  • That info is definitely useful. Although it doesn't tell me the command used to start the jvm (ie /usr/bin/java), it does something else for me. When I start the program using /usr/bin/java it shows all of the args that are passed. However, when I start using /usr/bin/jdb, the RuntimeMXBean shows the additional arguments of -Xdebug and -Xrunjdwp:transport=dt_socket,address=hostname.local:58481,suspend=y
    So I think jdb actually starts the normal jvm with the extra args (which makes sense too). But it would still be nice to know the entire command.     – TejasInstrument Nov 23 '10 at 22:36

2 Answers2

1

You can use JMX:

List<String> args = ManagementFactory.getRuntimeMXBean().getInputArguments();
AlexR
  • 114,158
  • 16
  • 130
  • 208
-1

With JDK 6, there is command named jinfo which helps you to identify what arguments provided

You just need to your Process Id, and to know that, you can use jps command, it will show you all running jvm processes and ids.

So with below command, you can able to get all command line passed. With the same command you can change some property dynamacally(just see jinfo -h)

jinfo

Narendra Shah
  • 11
  • 2
  • This utility is unsupported and may or may not be available in future versions of the J2SE SDK: http://docs.oracle.com/javase/1.5.0/docs/tooldocs/share/jinfo.html#options – Vikram Oct 10 '12 at 21:24