Editing Namespace (section)

=====Java=====
In [[Java (programming language)|Java]], the idea of a namespace is embodied in [[Java package]]s. All code belongs to a package, although that package need not be explicitly named. Code from other packages is accessed by prefixing the package name before the appropriate identifier, for example <code>class String</code> in <code>package [[java.lang]]</code> can be referred to as <code>java.lang.String</code> (this is known as the [[fully qualified name|fully qualified class name]]). Like C++, Java offers a construct that makes it unnecessary to type the package name (<code>import</code>). However, certain features (such as [[reflection (computer science)|reflection]]) require the programmer to use the fully qualified name.

Unlike C++, namespaces in Java are not hierarchical as far as the syntax of the language is concerned. However, packages are named in a hierarchical manner. For example, all packages beginning with <code>java</code> are a part of the [[Java platform]]—the package {{Javadoc:SE|package=java.lang|java/lang}} contains classes core to the language, and {{Javadoc:SE|package=java.lang.reflect|java/lang/reflect}} contains core classes specifically relating to reflection.

In Java (and [[Ada (programming language)|Ada]], [[C Sharp (programming language)|C#]], and others), namespaces/packages express semantic categories of code. For example, in C#, <code>namespace System</code> contains code provided by the system (the [[.NET Framework]]). How specific these categories are and how deep the hierarchies go differ from language to language.

[[function (programming)|Function]] and [[class (computer science)|class]] [[scope (programming)|scope]]s can be viewed as implicit namespaces that are inextricably linked with visibility, accessibility, and [[object lifetime]].