It is important to organize modules so that they can be easily located. The module path, a sequence of module components or directories, provides the organizational structure used by searches. These path components are searched for in order, returning the first path component that comprises a module.

Modules and their paths should not be considered to be the same as packages or classpaths. They are indeed different and have a greater level of fidelity. The key difference is that, with classpaths, a singular component is searched for. Module path searches return complete modules. This type of search is possible by searching the following paths, in the presented order, until a module is returned:

• Compilation module path
• Upgrade module path
• System modules
• Application module path

Let's briefly review each of these paths. The compilation module path is only applicable at compile time and contains the module definitions. The upgrade module path has the compiled module definitions. The system modules are built-in and include Java SE and JDK modules. The final path, the application module path, has the compiled module definitions from the application modules as well as the library modules.