1 field is changed---fanuction's parameter
2 behavior is changed---lambda for java8
3 block of codes is changed---class abstact interface
4 object is changed---design code or named frame
it is so important that..........
changes is our think<-->final is the frame about class abstract interface
so,
1 what is a funtion
changes to a field
2 what is a lambda
changes to a function
3 what is a class
changes to a bolck codes
4 what is a design code or frame
changes to a object