inheriting a class

Will someone please give me a hint on how I can get my parent class to inherit another class, for example, the chart data structure?

Of course, if you want to use an interface, use "implements" in the class declaration. A class can extend at most one other class (and, in fact, has to...if you don't declare a super class, you by default get the "Object" class as your super class. The Object class is the only class that does not have a super class.) However, it can implement any number of interfaces:

Of course, don't confuse the "is-a" with the "has-a" relationship. A HomoSapiens is a Chordata (going back enough super classes); but it has a Spine (making it a member of the Vertebrata sub-phylum, but that's a bit too involved for this example... )
I hope that this answers your question and does not confuse you further...

Go to http://mindview.net/Books and download the excelent free book "Thinking In Java". Then get the example code as well. Bruce Eckel wrote a very good chapter on inheiritence and Object Oriented Design. Work through the first 3 or 4 chapters of that book and you'll understand it perfectly.
Hope it helps.
Greg