| ExecutionContext | 
 This class models an execution context (transaction, security, etc) 
 with which the Work instance must be executed. 
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| Work | 
 This models a Work instance that would be executed by a 
 WorkManager upon submission. 
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| WorkContext | 
 This class serves as a standard mechanism for a resource adapter to propagate
 an imported context from an enterprise information system to an application
 server. 
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| WorkEvent | 
 This class models the various events that occur during the processing of
 a Work instance. 
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| WorkException | 
 A common base class for all Work processing related exceptions. 
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| WorkListener | 
 This models a WorkListener instance which would be notified
 by the WorkManager when the various Work 
 processing events (work accepted, work rejected, work started, 
 work completed) occur. 
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| WorkManager | 
 This interface models a WorkManager which provides a facility
 to submit Work instances for execution. 
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| WorkRejectedException | 
 This exception is thrown by a WorkManager to indicate 
 that a submitted Work instance has been rejected. 
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