1. Automating crediting of PIN into account
When PIN of equivalent amount is purchased, it is confirmed to be valid and then credited into the holders account.
2. Account switching
When an account holder request for money from an external source, it is pilled in from the interfacing central account and otherwise if the case is debiting.
Java, C programme and php are the programmes I thought neccesary otherwise the developer choose the ones he/she thought important.