15. At least one non-transitory computer readable storage medium having computer program instructions stored thereon that are arranged to perform the following operations: receiving a training and execution plan that specifies invocation of a trainer operator for initiating training of a trainee operator based on a set of training documents so as to generate a trained operator that is to then be invoked so as to extract information from one or more unknown documents, wherein the trainee operator is configured to extract information from one or more unknown documents and each training document is associated with classified information; after receipt of the training and execution plan, automatically executing the trainer operator to train the trainee operator based on the specified training documents so as to generate a trained operator for extracting information from documents; after receipt of the training and execution plan, automatically retaining the trained operator for later use in extracting information from one or more unknown documents; and after receipt of the training and execution plan, automatically executing the trained operator on one or more unknown documents so as to extract information from such one or more unknown documents.
15. At least one non-transitory computer readable storage medium having computer program instructions stored thereon that are arranged to perform the following operations: receiving a training and execution plan that specifies invocation of a trainer operator for initiating training of a trainee operator based on a set of training documents so as to generate a trained operator that is to then be invoked so as to extract information from one or more unknown documents, wherein the trainee operator is configured to extract information from one or more unknown documents and each training document is associated with classified information; after receipt of the training and execution plan, automatically executing the trainer operator to train the trainee operator based on the specified training documents so as to generate a trained operator for extracting information from documents; after receipt of the training and execution plan, automatically retaining the trained operator for later use in extracting information from one or more unknown documents; and after receipt of the training and execution plan, automatically executing the trained operator on one or more unknown documents so as to extract information from such one or more unknown documents. 17. The least one computer readable storage medium as recited in claim 15 , wherein the trainee operator is a previously trained operator and execution of the trainer operator is accomplished by: copying a plurality of immutable properties and values from the trainee operator and associating the copied immutable properties and values with the trained operator; and after execution of a learning algorithm results in a set of final mutable properties based on the training data and the trainee operator, associating the final mutable properties with the trained operator, wherein the final mutable properties include one or more of the following: a rule set specifying how to classify information, a plurality of weights for correlating one or more information features of a document with a particular classification result, a model for extracting information from a document, or thresholds for the number of features to consider.