Java command line option using @ symbol

Question

When invoking the 'java' process, I'm almost certain there is a way to have Java expand the contents of a file into a set of additional command-line arguments using the "@" symbol.

Something like:

java @myfile -cp foo -Dbar=baz com.mydomain.MyApp

And then the contents of "myfile" will be used as additional parameters.

It doesn't seem to work, but I'm certain that something very similar used to work. I've searched high and low but can't find anything on the InterNETs to help. Its driving me nuts! Someone please refresh my memory or lock me up.

What operating system are you using? This is easy to do in Unix. — David R Tribble
– David R Tribble, Commented Oct 29, 2009 at 23:02
For the record, this was added to the Java launcher (java/javaw) with Java SE 9. Prior to that release, only the compiler supported it. — Ti Strga
– Ti Strga, Commented Aug 27, 2020 at 16:07

David Z · Accepted Answer · 2009-10-29 22:12:06Z

11

It's probably the compiler you're thinking of:

javac [ options ] [ sourcefiles ] [ classes ] [ @argfiles ]

http://java.sun.com/javase/6/docs/technotes/tools/solaris/javac.html

answered Oct 29, 2009 at 22:12

David Z

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1 Comment

Mark Rotteveel Over a year ago

Since Java 9, it is also supported on java.

Jon Skeet · Accepted Answer · 2009-10-29 22:09:40Z

1

I've never seen anything like that in any JVM I've used.

Are you sure it wasn't a specific Java application, e.g. Ant or something similar?

answered Oct 29, 2009 at 22:09

Jon Skeet

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Brian Agnew · Accepted Answer · 2009-10-29 22:09:44Z

1

@ doesn't mean anything from the Java perspective. However in a DOS .BAT file it indicates that the files contained in the referenced file will be used.

e.g. DEL @FILENAME.TXT means that DOS will delete the files listed in FILENAME.TXT

I suspect that's what you're thinking of.

answered Oct 29, 2009 at 22:09

Brian Agnew

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PhiLho Over a year ago

In what shell? Not XP's cmd one at least, and never saw in regular Dos either.

Bostone · Accepted Answer · 2009-10-29 22:11:56Z

1

java VM takes options outlined in this document. I may be wrong but I never see anything what you described. So it could be something to do with shell you are using

answered Oct 29, 2009 at 22:11

Bostone

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Jé Queue · Accepted Answer · 2009-10-30 00:04:19Z

0

Shell expansion is to what you're referring?

jvmargs=-Xmx786m -Dfoo=bar
java $jvmargs com.foo.Bar

.

set jvmargs=-Xms786m -Dfoo.bar
java %jvmargs% com.foo.Bar

answered Oct 30, 2009 at 0:04

Jé Queue

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PhiLho · Accepted Answer · 2009-10-29 22:59:16Z

-1

It is a quite common practice/convention, but I believe you have to implement it yourself (ie. get the filename, open it, read and parse it...).

answered Oct 29, 2009 at 22:59

PhiLho

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