Reflection

Definitions

A language capability that allows a program to inspect and manipulate its own structure at runtime — querying class names, method signatures, field types, and annotations, and optionally invoking methods or modifying fields dynamically without compile-time knowledge of the types involved.
In plain English: A program's ability to look at its own internal structure while running — like reading its own blueprint — and act on what it finds.
Example: "The ORM uses reflection to map database columns to class fields without requiring you to write any boilerplate mapping code."