Difference between -D and -X options while passing parameters to JVM.

[NareshAnkuskani Kumar]

In maven we use maven_opts to pass parameters to the Java VM.

E.g. : set MAVEN_OPTS=-Xdebug -Xnoagent -Djava.compiler=NONE -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000

I am aware of the -D option. It is used to send the java system property. What exactly '-X' option represent?

I am aware of the -Xms, -Xmx options which are used to set the heap size.

In the above example what exaclty the line/point "-Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000" represent or what is does?

Thanks in advance.

Regards,
Naresh.

[Tim Holloway]

X stands for eXtension. Any "X" parameter is vendor-specific, and unlike the other options isn't guaranteed to be available on all JVM implementations - for example, IBM's jikes or the open-source IcedTea VMs.

[Mariana Costa]

So if -X for eXtension, what does -D stands for?

[Tim Holloway]

Mariana Costa wrote:So if -X for eXtension, what does -D stands for?

"define". I've used it in Kettle to pass in alternative package paths for custom plugins when I didn't want them in the main Kettle package hierarchy.

[Peter Johnson]

The -D is used to set system properties. Any Java code can then access any property so defined via System.getProperty().

[Martijn Verburg]

And welcome to Javaranch Mariana!

[Mariana Costa]

Tim Holloway wrote:

Mariana Costa wrote:So if -X for eXtension, what does -D stands for?

"define". I've used it in Kettle to pass in alternative package paths for custom plugins when I didn't want them in the main Kettle package hierarchy.

Ah, "Define"! Very creative =)
Thanks Tom.