(1) A processing step that prepares a program to be run. Activation can include allocating and initializing static storage for programs in a job and completing some portions of binding.
(2) In Java, the process of transferring an enterprise bean from secondary storage to memory. (Sun) See also passivation.
(3) The attachment of an activity to perform one of a series of processing steps. In order to perform all its processing, an activity may need to be activated several times. In between, it "sleeps". See also pseudoconversational.