Re: changing the classpath at runtime in code

From:
=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 24 Oct 2007 21:31:47 -0400
Message-ID:
<471ff1f7$0$90263$14726298@news.sunsite.dk>
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).


You posted this in the original thread but as noted in the linked to
thread almost all the classes I am dealing with *WILL* be in the
classpath.... so the question remains if I do the code in my previous
post will it now load from the class path or from "foo".


If the class get loaded by the parent classloader because it is
in the apps general classpath, then you can (as far as I know)
neither get it unloaded or reloaded.

You need to get those classes of the classpath.

Arne

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