Petals ESB Container

ExecutionContext is used in PetalsExecutionContext, the main entry point to store flow-related information for logs. It is a MDC-like implementation using Properties objects. The problem with it is that it relies on a recursive Properties objects: every time a thread is created, a new Properties object is created (this is ok) using the previous thread as a parent (this is not ok). When used in Thread pools, often threads of the pool are responsible of creating new threads, and thus after a long time, we can find ourselves with a very long chain of inheriting Properties object, and after a very very long time, this can result in StackOverflowError when trying to resolve properties in them. Hence, we should switch from the use of ExecutionContext to a better MDC implementation, such as the one provided by default by SLF4J, since it is a future plan to switch to SLF4J (PETALSDISTRIB-135).