The MIDlet lifecycle defines the execution states of a MIDlet, as well as valid state transitions. The lifecycle can be considered to start when the MIDlet is installed on a device and it lasts until the MIDlet is uninstalled. Most of the lifecycle functions are concentrated on the time when the MIDlet is starting, active or shutting down. When a MIDlet suite is installed on a device, its classes, resource files, arguments, and persistent storage are kept on the device and ready for use. The MIDlet(s) are managed and made available to the user via the device's Application Management Software (AMS).
In other words, as long as you meet the MIDlet requirements, the S60 and Series 40 platforms manage installation and uninstallation of the applications. When you follow the requirements in Implementing MIDlet lifecycle requirements, the AMS manages the MIDlet lifecycle of the application.