A Bundle start/stop operation activates/deactivates the bundle services. The associated class loader and wiring is unaffected.

Approach #1 - start/stop is not mapped to deployment operations

Bundle deploy installs the Bundle to the Framework
Bundle is not resolved/started as part of the deploy operation
No module/classloader is created during deployment
All deployment processing that needs load classes/resources is skipped
No service provided by the bundle deployment is created
Bundle needs to be started/stopped explicitly
Bundle start/stop management operations are specific to bundle deployments
The POST_MODULE processing for OSGi enabled deployments (e.g. webapp) would need to be executed in an OSGi specific processor chain
OSGi enabled POST_MODULE DUPs have their functionality externalised such that it can get reused for start/stop operations
The start/stop processing chain must be traversable in both directions repeatedly

Approach #2 - start/stop is mapped to deployment operations

Bundle deploy installs the Bundle to the Framework and attempts to resolve/start the Bundle
If the Bundle can get resolved, a module/classloader is created as part of the DU processing
In case the Bundle cannot get resolved, DUP processing is deferred and MODULE phase processing is reattempted later based on an external trigger
Has the benefit that any deployment type can also be a Bundle
Bundle stop must reverse work that is done in POST_MODULE DUPs
POST_MODULE DUPs must be traversable in both direction multiple times

Currently, we use approach #2 with limited support from POST_MODULE DUPs (i.e. they are not designed to be executed multiple times for the same deployment). There is also the cleanup phase which breaks multiple executions of POST_MODULE DUPs.