The first half of this introduction to Java inheritance teaches you how to use the extends keyword to derive ... ever-more-specific categories. As an example, Figure 1 shows car and truck ...

Inheritance and composition ... it is also clear that this code does not pass the “is a” test. Now let’s try the same example using composition: import java.util.HashSet; import java.util ...

You believe clean code ... Use sealed classes in Java to control your inheritance Need to limit the number of possible subclasses in your codebase? Here comes Java's sealed classes to your rescue.