## About Module Installers

See Also

A module installer is a Java class that provides hooks for running code on startup or when a module is loaded. It can also run cleanup code when a module is uninstalled or disabled.

In general, using a module installer is not recommended, because it slows down startup time. Before using a module installer, make sure that there is no declarative way of doing what you are trying to do. The main declarative way of installing items, is to put a file in your JAR's `META-INF/services` directory or creating an XML layer file that declares information about the items your module is installing. Then, when they are needed to do actual work, your items will be instantiated.

In addition to providing a module installer class, you need to add an entry to the `MANIFEST` file. The Module Installer Wizard creates a skeleton implementation of a module installer, adds the entry to the `MANIFEST` file, as well as entries to the `project.xml` file, which provides the module's metadata.

For an example of an implementation of a module installer, see:

See Also
  About NetBeans Platform and Module Development
  About the NetBeans Platform

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