etter for <code>ExecutionContext</code> 
 to be a class rather than an interface: 
 <ul><li>There is no need for a resource adapter to implement this class. 
 It only needs to implement the context information like 
 transaction, etc.
 <li>The resource adapter code does not have to change when the 
 <code>ExecutionContext</code> class evolves. For example, more context 
 types could be added to the <code>ExecutionContext</code> class 
 (in the future) without forcing resource adapter implementations 
 to ch