In Java, a package is a mechanism used to group related classes, interfaces, enumerations, and annotation types together into namespaces, providing a unique namespace for each type it contains. Packages are used to avoid naming conflicts and to write better maintainable code.
A package can contain the following types of classes: classes, interfaces, enumerations, and annotation types. A package allows a developer to group classes (and interfaces) together. These classes will all be related in some way – they might all have to do with a specific application or perform a specific set of tasks. Programmers also typically use packages to organize classes belonging to the same category or providing similar functionality.
Packages are divided into two categories: built-in packages (packages from the Java API) and user-defined packages (packages created by developers). Built-in packages are a part of the Java API and contain a large number of classes that are free to use, including components for managing input, database programming, and much more. User-defined packages are created by developers and are stored in a file system directory, similar to folders on a computer.
When a package declaration is not used, classes are placed in an unnamed package. Classes in an unnamed package cannot be imported by classes in any other package. It is generally advised to avoid using unnamed packages, and instead, classes and interfaces should belong in named packages.
In summary, a package in Java is a way to organize related classes, interfaces, enumerations, and annotation types into namespaces, providing a unique namespace for each type it contains. Packages are used to avoid naming conflicts and to write better maintainable code. There are two types of packages: built-in packages and user-defined packages.
