It means that it can be extended. When COBOL was written, all the commands and actions allowable were inbedded in the COBOL compiler. As a programmer I could not invent new commands and use them. In java you can invent new classes and methods and use them. Therefore it is extensible. You can take on class libraries and they interact with the JRE seamlessly. The same thing with XML. HTML has a set of tags that can be used, and thats it. Whatever set the browser supports is what you get. XML on the other hand, allows the programmer to invent new tags and use them interactively with HTML tags.
"JavaRanch, where the deer and the Certified play" - David O'Meara
Extensible basically means that you can expand on what is currently built. So if someone has a class that they have built, you can use that class and build on that even more. I may make a class called Graph that accesses the graphipcs library and builds some simple graphs for me. If I leave exposed some of the functionality of this class, you may be able to build on it. Example, you might create a class that extends from Graph called BarGraph and yet another one called PieGraph. This makes the language very powerful and makes code reuse a key component of the language. Dale
------------------ By failing to prepare, you are preparing to fail. Benjamin Franklin (1706 - 1790)
By failing to prepare, you are preparing to fail.<br />Benjamin Franklin (1706 - 1790)