asp.net - HttpApplication.Init vs HttpModule.Init -

i trying understand why init method available in both httpapplication , httpmodule, , when use 1 on other.

you can have 1 application, can have multiple httpmodules within 1 application. modules used handle separate blocks of functionality can added application (few real life examples - elmah - handles error logging, identitymodule - handles impersonation, etc.). since can attach same module (lets error logging) different application (lets mycompany.crm, mycomany.publicweb, mycomany.intranet), makes sense handle initialization on own, intepended on application you're adding them to.