Scope Rules

• Scope rules are used to determine the specific object or method that is being referenced when an identifier is used.

• In Java, scope is determined by blocks of code (code within curly braces) and the class hierarchy of the current instance.

• When Java needs to resolve an issue of scope, it looks for an identifier's definition in the following order (and stops looking when the identifier is found):
  
  
  1. the current block
     
     
  2. surrounding blocks
     
     
  3. the class of the current instance (or current object)
     
     
  4. the superclasses of the current instance's class hierarchy
  
  
• This means that a local object with the same name as an instance variable will be found and used, not the instance variable.

• It is a good idea to avoid using the names in a class or its superclass(es) for local variables.

• If you do have local variables with the same identifier names and want to access the instance variables, use this.