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Using separate classpaths for separate classes?

Frank Fredstone
Posts: n/a
I need to use classes that require conflicting classpaths, and I have
no access to source code.

Can I instantiate a class with one classpath in effect so that all the
classes it uses are resolved from their classpath, and then
instantiate a different class with a different classpath, so that all
the clasess it uses are resolved from that separate classpath?

Will it work to use URLClassLoader for this? It's not working for me,
but I think I might be making a mistake.

Should it work like this:

URLClassLoader clA = new URLClassLoader(new URL[] {
new URL("file:///somewhere/some-a.jar"),
Class ca = clA.loadClass("some.ClassA");
Object oa = ca.newInstance();

URLClassLoader clB = new URLClassLoader(new URL[] {
new URL("file:///somewhere/some-b.jar"),
Class cb = clB.loadClass("some.ClassB");
Object ob = cb.newInstance();

Then when some.ClassA instantiates some.OtherClass1 and
some.OtherClass2 (invisible to me), they will be loaded from

And, when some.ClassB instantiates some.OtherClass1 and
some.Otherclass2 (invisible to me), they will be loaded from

So, some.ClassA will never load anything from some-b.jar and
some.ClassB will never load anything from some-a.jar.
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Jean-Francois Briere
Posts: n/a
Should work.
Make sure that some-a.jar and some-b.jar are NOT is the JVM class path.


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