How to get list of classes from a package

[Rémi Forax]

Tom Hawtin a écrit :
> David M. Lloyd wrote:
>> On 02/16/2009 10:22 AM, Ulf Zibis wrote:
>>>
>>> can anybody tell me, how I could get al list or enumeration of the 
>>> classes, which belong to a package.
>>> I can't see any appropriate method in java.lang.Package :-(
>>
>> This isn't really possible at run time, since one doesn't know 
>> whether a class exists until one tries to load it.  The classloader 
>> might not even know.  Also, a package can span classloaders, adding 
>> more complexity to the problem.
>
> IIRC, you will get a different Package for each class loader, for a 
> given package name. Certainly classes with the same package name will 
> not have Java access to default/protected 
> members/classes/interface/constructors from different class loaders.
>
> But yes, a list of classes is not necessarily complete. Also, IIRC, 
> Proxy dynamically inserts classes into packages as well.
>
> Tom Hawtin
Ulf, if you can create an agent, you can get all loaded classes:
http://download.java.net/jdk7/docs/api/java/lang/instrument/Instrumentation.html#getAllLoadedClasses()

But if you want thoses classes to find some that implement an interface,
java.util.ServiceLoader is your friend:
http://download.java.net/jdk7/docs/api/java/util/ServiceLoader.html

cheers,
Rémi