Re: changing the classpath at runtime in code

From:

Daniel Pitts <newsgroup.spamfilter@virtualinfinity.net>

Newsgroups:

comp.lang.java.programmer

Date:

Wed, 24 Oct 2007 19:26:10 -0700

Message-ID:

<0cydnSz-O78vjr3anZ2dnUVZ_jKdnZ2d@wavecable.com>

Aryeh M. Friedman wrote:

On Oct 24, 9:13 pm, Arne VajhHj <a...@vajhoej.dk> wrote:

Aryeh M. Friedman wrote:

On Oct 24, 8:16 pm, Arne VajhHj <a...@vajhoej.dk> wrote:

Aryeh M. Friedman wrote:

Is it possible for a java app to change it's classpath at runtime. I
tried:
System.setProperty("java.class.path","foo")
The reason for wanting to try is URLClassLoader will not physically
reread a class file if it is in the classpath.

Create a URLClassLoader with a url that are *not* in the parent
classloaders url's.

so just do:
URL[] url={new URL("file://foo")};
URLClassLoader laoder=new URLClassLoader(url);
?

I have a little demo example I often use to illustrate
(subdir test is not in classpath of program).

Perhaps google ate my previous response.... but as I said several
places (including the linked to thread) almost all my classes *WILL*
be in the classpath... btw as mentioned in an other thread your demo
doesn't quite work once divorced from the code to rewrite the class
(see orginial thread)... so the question remains does the code above
load from "foo" or from the classpath when I do loader.loadClass(...)

Here's the scoop.
If its ever on the class path, you can't reload it. What you're trying
to do is not possible to do without restricting what's on the class
path. That is not a bad restriction! Just make it happen.

Changing the class path after the fact isn't going to help either.

--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>