A namespace in Joomla organises PHP classes and helps avoid name collisions. It forms part of a class’s fully qualified name.
Relationship to files
Modern Joomla extensions use namespaces with autoloading. A prefix-to-directory mapping locates class files without manually including each one. Extension namespace information can be declared in its manifest.
Developer checks
Namespace names, paths, letter case and class names must match the expected structure. A Joomla Class not found error may indicate registration or file-layout problems rather than a missing extension. A namespace is not a URL alias or database table name.
Use Joomla namespaces consistently with autoloading rules. This makes extensions easier to maintain and combine.