[equinox-dev] Change in TCCL when BundleActivator.start() is called

[Andy Wilkinson <andy.wilkinson@xxxxxxxxxxxxxxxx>]

Hi,

I've been looking into a problem with a user's application that was 
working ok on top of Equinox 3.4.2, but is now failing with a 
ClassNotFoundException when running on top of Equinox 3.5.

We have some code that, prior to starting a bundle, sets the Bundle's 
ClassLoader as the TCCL, and then restores the old TCCL once start has 
completed. This works as expected on 3.4.2. Running on 3.5, the Bundle's 
ClassLoader is overwritten by a ContextFinder instance as part of 
Equinox's start processing.

I've done some archaeology and I think I've tracked it back to the 
changes made under 258209:

"This patch also ensures the TCCL is set to the ContextFinder for each 
call to BundleActivator.start()."

I'm interested to learn about the reasoning behind this change. It 
strikes me as a little bit odd that ContextFinder is the TCCL as this is 
something of an Equinox implementation detail, where's the Bundle's 
ClassLoader is not. As far as I know, the OSGi spec is silent on what 
the TCCL should be when an activator is called so I realise that Equinox 
has some freedom in this area. That said, the change has broken an 
application that works fine on 3.4.2 so, in our case at least, we'd 
prefer that things were the way they were before.

Thanks,
Andy