When you create class members like properties and methods, you can define their scope using specific ActionScript keywords.
Private , Public, Protected, Override and others are access modifiers for the OOP language, and each have a different meaning and usages. I have mention some of access modifiers description below.
The public keyword is top level access modifier. It gives access to all over packages. It mean you can access public memebr in any of the call or any of the package. There is no restriction to access this type of memebr.
The protected keyword one step down to public access modifier. It give access to them from which calss it is declared also in the class declared this member.
The internal keyword gives internal access to member, which is accessible only within files in the same assembly.
The private keyword gives private access to memebr, which is the lowest permissive access level to memebr. This type of members are accessible only within class or where they has beed defined. It will give you a compile time error if you try to access this type of member outside of the class.
The override keyword Indicates that a method declaration is intended to override a method declaration in a superclass. It used to extend the implemented functinality or add new functinality in that method or superclass.
The static keyword used with the class, field, method, properties, operator, event and constructors.When we use static modifier with the members then they are no more part of instance of a class. Static members are a part of class itself.
The final keyword used with class ,when used in a class declaration, the final keyword means the a class can't be subclassed. In other words, no other class can extend (inherit) a final class, If you try to extend the final class it will give you compile time error.