How to code with OOP concept
This section, I try to give the sample on how to code in Java using object oriented concept (we'll talk OOP concept). we must have known at least four concept to code in pure object oriented concept. encapsulation, in this sample program, how we add private as acces specifier for the variables sisi, panjang and lebar (see more in the program that you can download at the link).
The second, we add inheritance see (class persegiPanjang extend BangunDiatar), so the class of BangunDatar can get the met hod from class both Persegipanjang and BujurSangkar. here is the link to download code recommendedOOPSample
Finally, we add inheritance see (class persegiPanjang extend BangunDatar), so the class of BangunDatar can get the method from class both Persegipanjang and BujurSangkar. Now please try the code usign editors of Java (e.g : NetBeathen, Eclipse or others).