Re: In which circumstances a Class.forName() can fail?

From:

Eric Sosman <esosman@ieee-dot-org.invalid>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 04 Jun 2009 09:23:36 -0400

Message-ID:

<h08hsr$eci$1@news.eternal-september.org>

Ivo wrote:

On Jun 4, 2:54 pm, Eric Sosman <esos...@ieee-dot-org.invalid> wrote:

Ivo wrote:

Hello to all,
In which circumstances a Class.forName() can fail, when the String
comes from the STE class ???
(I have been getting ClassNotFoundException, which should never happen
by my knowledge :( )
here is the code snippet:
final String className = stackTraceElement.getClassName();
        Class clazz;
        try {
            clazz = Class.forName(className);
        } catch (final ClassNotFoundException cnfe) {
            // should be totally impossible since any Class having
methods locked in a stack
            // frame cannot be removed from VM.
// throw new IllegalStateException(cnfe);
            return null;
        }

Class.forName(String) is documented as being equivalent
to Class.forName(String, true, currentLoader), where the final
argument is the current ClassLoader. If the class you are
looking for was loaded by a different ClassLoader, I imagine
that looking for it with the wrong ClassLoader might fail.

The STE is straight from a trace obtained from the current Thread, all
of which is still in scope, so not GCed.

I don't see what difference that makes. Threads are not
ClassLoaders, and ClassLoaders are not Threads, and neither
Threads nor ClassLoaders are garbage collectors.

I don't know whether your problem is or is not caused
by a ClassLoader mismatch -- how could I? -- but just
suggesting that it's something to consider.

--
Eric Sosman
esosman@ieee-dot-org.invalid