Re: Installing Extensions to JREs properly

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.help
Date:
Tue, 7 Apr 2009 15:29:14 -0700 (PDT)
Message-ID:
<944014c4-f245-4fdd-a79d-e8de25991a16@q9g2000yqc.googlegroups.com>
Dave Smith wrote:

My only issue would be that I think the RXTX source is hard coded to
look in the JRE directory, and I might have to try and find a way to
override that. That shouldn't be too difficult, though.


Sun explains the "optional packages" (erst "extensions") mechanism
here:
<http://java.sun.com/javase/6/docs/technotes/guides/extensions/
index.html>

For a third-party library that insists on pretending to be part of the
Java core API, which is what extensions do, you might get some joy
from the 'java' executable option
    -D java.ext.dirs=/some/directory

Also, according to the tutorial referenced linked from the above URL,
at
<http://java.sun.com/docs/books/tutorial/ext/basics/install.html>
they tell us:

Prior to Java 6, the value of java.ext.dirs referred to a single director=

y,

but as of Java 6 it is a list of directories (like CLASSPATH) that specif=

ies

the locations in which extensions are searched for. The first element of =

the

path is always the lib/ext directory of the JRE. The second element is a
directory outside of the JRE. This other location allows extension JAR fi=

les

to be installed once and used by several JREs installed on that system.


I find it very useful to peruse java.sun.com for answers to these
kinds of questions. To find your answer, I started my search at:
<http://java.sun.com/javase/6/docs/>

--
Lew

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