Are there cases where Android would start an app/service other than due to Intents or explicit user start? I'm trying to understand how/why some of the processes that are running on my phone (DroidX, stock 2.2 ROM).

It's obvious that 2 likely reasons for a process to start are:


A direct action by the user/another program to start it (e.g. click on the icon of an app, or another process launches the .apk explicitly)
An Intent is registered by the app, and the event associated with that intent happens.


The question is, are there other reasons/causes/mechanisms by which a process could be started in Android? (aside from Intents or direct launch).

P.S. As a plausible theory, something could be started off of init.rc (being how Android is based off of Linux) but I don't know enough about Android internals to judge if it launches any apps via init.rc
A raw native process can be created by any of the usual unix-like mechanisms.

An android activity or service is usually forked off by zygote (in response to an intent), but I think there's an obscure way to start a vm by hand using app_process.