I have two classes  ClassA and ClassB with WITH SHARING and WITHOUT SHARING keywords respectively. 

Now what will happen if I call ClassB into ClassA?
On which context they finally Run Finally?
 

trigger code need
record type  id: 012Bg000000INcTIXX
when the stage will be 'converted - closed'   auto generate  account and contact and opportunity  based on record type (in after insert & after update)
 

Hey guys I'm new to salesforce and I've to update all phone numbers on contact when account phone number changes, how can I do this with trigger? please help.