+ 1 both for the longer term plan and the short term proposal

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> On 5 Jul 2016, at 13:56, Svetoslav Neykov 
> <[email protected]> wrote:
> 
> Brooklyn has a number of places where it will try to load a class by name. 
> It's either using Class.forName(..) or at best 
> mgmt.getCatalogClassLoader().loadClass(...). This is highly likely to fail 
> when run in Karaf.
> Some examples of this behaviour:
>  * configuring entitlements implementation in brooklyn.properties (or 
> configuring any other class name for that matter)
>  * initializers/enrichers in yaml
>  * objects passed as config keys/sensors to an entity, with the entity not 
> knowing how to load the classes - can't rebind. For example Brooklyn DSL 
> deferred objects / SpecialFlagsTransformer passed as config
>  * PolicyResource trying to attach a policy by class name
> 
> Longer term we should introduce bundle knowledge in all of those places. 
> There are various ways to do that - ether by explicitly passing bundle 
> symbolycName + version, loading through a catalog item or another OSGi 
> mechanism altogether.
> Shorter term I suggest we go for the following workaround, giving us time to 
> introduce proper OSGi behaviour for each of the the above cases:
>  * Pull the class loading logic in a single place. Same as ResourceUtils, but 
> for classes.
>  * Support bundle symbolic name + version embedded in the class name - for 
> example 
> org.apache.brooklyn.policy:0.10.0.SNAPSHOT:org.apache.brooklyn.policy.ha.ServiceFailureDetector.
>  That will allow us to use the existing code paths to pass classes, but be 
> able to resolve them.
>  * Fall back to a white list of bundles to scan for the class name. For 
> example "org.apache.brooklyn.*:0.10.0.SNAPSHOT". This will help in parsing 
> existing yaml plans, using stock enrichers, rebinding.
> 
> Svet.

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