Double-clicking Java class file on Windows

Thread view:

hiwa - 03 Jun 2006 23:41 GMT

I know this really is a Windows issue but
I can't find its official documentation nowhere.

My question is: how to enable double-click
launching of a Java class which has main()
method, via Windows filetype association
mechanism?

If we can't do it, then, why it is?

Reply to this Message

Jeffrey Schwab - 04 Jun 2006 00:37 GMT

> I know this really is a Windows issue but
> I can't find its official documentation nowhere.
[quoted text clipped - 5 lines]
>
> If we can't do it, then, why it is?

Write a script that takes the name of the class file and spawns java
with appropriate arguments. For example, on Windows XP, I've created an
"Open" action for the .class file type, defined to run the following
command:

C:\ruby\bin\rubyw.exe -w C:\files\ruby\open.rb "%1"

The ruby script open.rb is something I can also use from the command
line to open files in my own wily ways. It looks like this:

begin
f = ARGV.shift or raise "usage: open <file> [args...]"
case f
when /\\([^\\]+)\.class$/
cmd = "javaw #{$1} #{ARGV}"
system(cmd)

# <snip>handling of other file types</>

else
raise "unknown file type: #{f}"
end
rescue Exception => x
STDERR.puts x
end

Reply to this Message

Luc The Perverse - 04 Jun 2006 01:17 GMT

>I know this really is a Windows issue but
> I can't find its official documentation nowhere.
[quoted text clipped - 5 lines]
>
> If we can't do it, then, why it is?

Jar file? Will work as long as winrar has not stolen the association.

--
LTP

Reply to this Message

Dale King - 04 Jun 2006 04:10 GMT

> I know this really is a Windows issue but
> I can't find its official documentation nowhere.
[quoted text clipped - 5 lines]
>
> If we can't do it, then, why it is?

To provide a more thorough answer, what you want is to package up the
classes correctly into a jar file. With an appropriately set-up
executable jar file you can double-click it to run it in Windoze.

For more information see:

http://www.google.com/search?hl=en&q=executable+jar&btnG=Google+Search

Signature

Dale King

Reply to this Message

hiwa - 04 Jun 2006 10:15 GMT

Dale King :

> > I know this really is a Windows issue but
> > I can't find its official documentation nowhere.
[quoted text clipped - 16 lines]
> --
> Dale King

Thanks. But the topic is not executable jar file.
I just have a naive question for plain Java class file and Windows
[open] action association.
Why we can't associate it with java or javaw command?

Reply to this Message

Ingo R. Homann - 07 Jun 2006 13:30 GMT

Hi,

>>>I know this really is a Windows issue but
>>>I can't find its official documentation nowhere.
[quoted text clipped - 18 lines]
> [open] action association.
> Why we can't associate it with java or javaw command?

This is because java/javaw wants the class-name without the extension
".class" (and with package-information instead of path-information).

Don't ask me *why* sun did not allow to give the class-filename as
parameter - I think that it would be a good idea, as well.

On the other hand - what's the problem to embed the classfile in a
jarfile? (You can avoid some classpath problems then, e.g....)

Ciao,
Ingo

Reply to this Message

Dale King - 10 Jun 2006 04:35 GMT

> Hi,
>
[quoted text clipped - 26 lines]
> Don't ask me *why* sun did not allow to give the class-filename as
> parameter - I think that it would be a good idea, as well.

I can tell you why because a program is not usually a single class file.
It is a bunch of class files arranged in a tree of packages. You have to
have some form of class path. Do you expect Java to deduce your class
path to find the rest of the classes?

Signature

Dale King

Reply to this Message

Ingo R. Homann - 12 Jun 2006 10:26 GMT

Hi,

>> Don't ask me *why* sun did not allow to give the class-filename as
>> parameter - I think that it would be a good idea, as well.
[quoted text clipped - 3 lines]
> have some form of class path. Do you expect Java to deduce your class
> path to find the rest of the classes?

I know. But in many cases, it would be enough, if java would use a
"default" classpath with the "current" directory (or the directory, in
which the classfile is placed). Indeed, that would be some kind of
deduction, but not very tricky:

Consider, you have some classes: "MainClass" in the default-package and
"packageA.subpackageX.OtherClass". Then your directories would be:

/application/bin/MainClass.class
/application/bin/packageA/subpackageX/OtherClass.class

Now, if you double-click on MainClass.class, what would be the problem
to "guess" where OtherClass is placed?

Two notes:

(1) I know that I must improve this logic, so that jar-files can be
found (as usual, "$APP/lib/*.jar")

(2) As I said: "On the other hand - what's the problem to embed the
classfile in a jarfile? (You can avoid some classpath problems then,
e.g....)"

Ciao,
Ingo

PS: Yes, I am aware that the word "subpackage" does not exist in java,
but I guess you know what I mean by this. :-)

Reply to this Message

Double-clicking Java class file on Windows

Free Magazines