What does namespace mean in Java?

In Java, the concept of a namespace is embodied in packages. A package is a way to group related classes, interfaces, and other types together to avoid naming conflicts and to organize code in a logical manner. Each package serves as a unique namespace for its contents, ensuring that classes with the same name can coexist as long as they are in different packages.

Here are some key points about namespaces (packages) in Java:

1. Fully Qualified Names: In Java, every class, interface, or member can be referred to by its fully qualified name, which includes the package name, class name, and member name. For example, java.lang.String is the fully qualified name for the String class in the java.lang package3.

2. Import Statement: To avoid having to use the fully qualified name every time, Java allows you to import classes or packages using the import statement. This brings the imported classes into the current scope, allowing you to use them without their package prefix13.

3. Hierarchical Organization: Although Java packages are not syntactically hierarchical like namespaces in some other languages (e.g., C++), they are often named in a hierarchical manner. For example, java.lang and java.lang.reflect are related but distinct packages1.

4. No Global Variables or Functions: Unlike some other languages, Java does not have global variables or functions. All fields and methods must be declared within a class, which helps maintain encapsulation and avoids naming conflicts3.

In summary, Java's package system acts as a namespace to organize and differentiate between classes and other types, ensuring clarity and preventing naming conflicts.