In short:
When using Parsley's Context for dependency injection, You should call destroyObject() on each getObject() call, otherwise you may have a memory leak.
 
Long story:
Lately I was dealing with some memory leaks issues in one of our client's systems which use Parsley for dependency injection via its Context .
Turns out that calling Context.getObject(id) internally creates references to the objects used for creating the injected object.
These references are not released, and may cause a memory leak.
The profiler (FB4) looks something like this (namespaces ommited for client's privacy sake):