Re: How to specify the main() class in "jar -cfe ..." ?

From:

Lew <noone@lewscanon.com>

Newsgroups:

comp.lang.java.help

Date:

Sat, 03 Apr 2010 22:53:37 -0400

Message-ID:

<hp8uve$itn$1@news.albasani.net>

Raymond Schanks wrote:

Assume I want to create a jar archive with a command

jar -cfe myjar.jar <MainApp> *.class

for some classes. The entrypoint should be the main() method in class
"MyTestclass123".

What do I have to specify for <MainApp> in the command above?

Do I have to write:

jar -cfe myjar.jar main *.class

or

jar -cfe myjar.jar MyTestclass123 *.class

What if the main() class is the only main() method in all classes. Can
I omit it then and write simply

jar -cf myjar.jar *.class

?

Alan Malloy wrote:

This is not done with the jar CLI.

Sure it is, sometimes.
<http://java.sun.com/javase/6/docs/technotes/tools/solaris/jar.html#options>
"e Sets entrypoint as the application entry point for stand-alone
applications bundled into executable jar file. The use of this option creates
or overrides the Main-Class attribute value ..."

Instead, you need to

Instead you may

include a special file in the jar, called a manifest.
It can specify lots of things, but of particular value for you is
that it specifies the main() class. Relevant links:

Manifest basics
http://java.sun.com/docs/books/tutorial/deployment/jar/manifestindex.html

Setting main() class
http://java.sun.com/docs/books/tutorial/deployment/jar/appman.html

This latter link comes highly, or at least frequently recommended.

--
Lew