1. A method for dynamically mapping Dynamic Multi-sourced Persisted EJB attributes to source system resources, comprising: creating a context definition containing attributes representing collections of source system data; specifying in an attribute mapping element whether each attribute in the context definition is mapped to a field in a data source; storing the context definition in a persistent data cache; creating an instance of a Dynamic Multi-sourced Persisted EJB; applying the attributes in the context definition to the created instance of the Dynamic Multi-sourced Persisted EJB for mapping the specified attributes to source system data fields; accessing mapped source system data by the Dynamic Multi-sourced Persisted EJB instance without requiring EJB compilation and deployment; and sending mapped attribute data from source systems to clients and from clients to source systems in response to client queries.