Re: ClassLoader, ambiguity between classes
On 07.12.2006 16:27, RS wrote:
I use a customised ClassLoader which can be called during runtime to load
all .class file present in a directory and its subs.
Why did you create a custom class loader for this? Also, this pattern
might not fit well with the usual approach, i.e. classes are loaded when
needed - not earlier. Especially your order of loading is likely
different from the order that would be imposed by class dependencies.
> Problem : when it reads
the classes in a folder which has allready been loaded. In this case,
several classes are loaded twice and I've this strange behaviour
Class c = this.defineClass(null,buffer,0,buffer.length);
print c.hashCode() --> gives
18602441
print Class.forName(c.getName()).hashCode() --> gives 3912376
is it possible to "unload" a class ?
I believe the JVM's GC will collect classes at some point in time (if
they are unused of course). But I doubt you can explicitly unload
classes because that would likely cause loose ends.
The thing is that I've no way to know the binary name of the class I'm
loading, so I cannot test if class has allready been loaded before... Any
idea ?
Can't you use some bytecode reading package like gnu.bytecode to inspect
the class file you are about to load?
My general recommendation is this: do not mess with class loading unless
you have to (i.e. write a servlet container or a JVM, have to fetch
classes from other sources than file system and jars). It is not easy
to get right and I cannot think of a standard application that would
actually benefit from this. My 0.02EUR...
Kind regards
robert