Why the Move to ActionScript 2.0
The release of Flash MX 2004 is not really a new version of ActionScript. What you now have is a continued evolution of what you already knew about ActionScript. The big difference, however, is the inclusion of many classes within Flash itself that enable you to program in OOP more easily.
The four new keywords are
If you have programmed with C or Java, you recognize these terms. They are not new or unique to Flash. The terms are industry standardsterms used by the leading OOP languages. ActionScript is now a real OOP language, not a pseudo-language. The ramifications of real OOP programming in Flash are strong enough that Macromedia decided that a new version of ActionScript needed to differentiate between the two versions.
Advantages of Working with ActionScript 2.0
As you begin to work more with ActionScript 2.0, you will find that it really is only an extension of the previous versions of ActionScript. What the new version now has to offer, however, is a path that enables Java developers to move from Java to ActionScript.