JModuleHelper::getModules($position);
$modules = JModuleHelper::getModules('top');
JModuleHelper::getModule($id);
$module = JModuleHelper::getModule(20);In conclusion, JModuleHelper is a PHP class in the Joomla CMS package library that provides various methods to retrieve modules from the database. The `getModules` method is used to retrieve an array of all the modules installed on a page, while the `getModule` method is used to retrieve a specific module by its ID.