After we study any language, we are not in a position to remember every thing. Therefore, a quick ready reference becomes very useful. In the following table, we have tried to summarize all the important rules, points, and facts about Java programming. If you get some errors and want to get some clue quickly without reading the entire text, the following table will be of great help to you.
||A class containing an abstract method is an abstract class. Such a class must be explicitly declared as abstract.|
||An abstract class cannot be instantiated.|
||If a class extends an abstract class, it must define all the methods of the super class. Otherwise, ...|