A source object implements or Realizes its destination object. Realize connectors are used in a Use Case, Component or Requirements diagram to express traceability and completeness in the model. A business process or Requirement is realized by one or more Use Cases, which in turn are realized by some Classes, which in turn are realized by a Component, and so on. Mapping Requirements, Classes and such across the design of your system, up through the levels of modeling abstraction, ensures the big picture of your system remembers and reflects all the little pictures and details that constrain and define it.
You can also define template binding parameters for a Realize connector between a binding Class and a parameterized Class.
OMG UML Specification:
The OMG Unified Modeling Language specification, (v2.5.1, pp.38-39) states:
Realization is a specialized Abstraction dependency between two sets of NamedElements, one representing a specification (the supplier) and the other representing an implementation of that specification (the client). Realization can be used to model stepwise refinement, optimizations, transformations, templates, model synthesis, framework composition, etc. A Realization signifies that the set of clients is an implementation of the set of suppliers, which serves as the specification. The meaning of “implementation” is not strictly defined, but rather implies a more refined or elaborate form in respect to a certain modeling context. It is possible to sp