# Components (Deprecated) Migrating deprecated plugin components to the current solutions. > When writing new plugins, creating Components must be avoided. > Any existing Components should be migrated to services, extensions, or listeners (see below). > {style="warning" title="Deprecation Notice"} Plugin Components are a legacy feature supported for compatibility with plugins created for older versions of the IntelliJ Platform. Plugins using Components don't support [dynamic loading](dynamic_plugins.md) (the ability to install, update, and uninstall plugins without restarting the IDE). Plugin Components are defined in the ``, ``, and `` sections in a [Plugin Configuration File](plugin_configuration_file.md). ## Migration To migrate existing code from Components to modern APIs, see the following guidelines. ### Manage State To manage some state or logic that is only necessary when the user performs a specific operation, use a [Service](plugin_services.md). ### Persisting State To store the state of your plugin at the application or project level, use a [Service](plugin_services.md) and implement the `PersistentStateComponent` interface. See [Persisting State of Components](persisting_state_of_components.md) for details. ### Subscribing to Events To subscribe to events, use a [listener](plugin_listeners.md) or create an [extension](plugin_extensions.md) for a dedicated extension point (for example, `com.intellij.editorFactoryListener`) if one exists for the event to subscribe to. ### Application Startup > Executing code on application startup should be avoided whenever possible because it slows down startup. > {style="warning"} Plugin code should only be executed when projects are opened (see [Project Open](#project-open)) or when the user invokes an action of a plugin. If this can't be avoided, add a [listener](plugin_listeners.md) subscribing to the [`AppLifecycleListener`](%gh-ic%/platform/platform-impl/src/com/intellij/ide/AppLifecycleListener.java) topic. See also [Running Tasks Once](ide_infrastructure.md#running-tasks-once). ### Project Open Using [Kotlin coroutines](kotlin_coroutines.md), implement [`ProjectActivity`](%gh-ic%/platform/core-api/src/com/intellij/openapi/startup/StartupActivity.kt) and register in `com.intellij.postStartupActivity` extension point. Examples: - [`PowerSaveModeNotifier`](%gh-ic%/platform/lang-impl/src/com/intellij/ide/actions/PowerSaveModeNotifier.kt) - [`TipOfTheDayStartupActivity`](%gh-ic%/platform/tips-of-the-day/src/com/intellij/ide/TipOfTheDayStartupActivity.kt) Implementation in [Kotlin](using_kotlin.md) is required because Java doesn't support suspending functions. To execute code when a project is being opened, use one of these two [extensions](plugin_extensions.md): `com.intellij.postStartupActivity` : [`StartupActivity`](%gh-ic%/platform/core-api/src/com/intellij/openapi/startup/StartupActivity.kt) for immediate execution on EDT. Implement `DumbAware` to indicate activity can run in a background thread (in parallel with other such tasks). `com.intellij.backgroundPostStartupActivity` : [`StartupActivity.Background`](%gh-ic%/platform/core-api/src/com/intellij/openapi/startup/StartupActivity.kt) for execution with a 5-second delay in a background thread (2019.3 or later). Any long-running or CPU-intensive tasks should be made visible to users by using `ProgressManager.run(Task.Backgroundable)`. Access to indexes must be wrapped with [`DumbService`](indexing_and_psi_stubs.md#dumb-mode), see also [General Threading Rules](threading_model.md). See also [](ide_infrastructure.md#running-tasks-once). ### Project and Application Close To execute code on project closing or application shutdown, implement the [`Disposable`](%gh-ic%/platform/util/src/com/intellij/openapi/Disposable.java) interface in a [Service](plugin_services.md) and place the code in the `dispose()` method. Alternatively, use `Disposer.register()` passing a `Project` or `Application` service instance as the `parent` argument (see [Choosing a Disposable Parent](disposers.md#choosing-a-disposable-parent)).