Subclasses are classes that inherit from parent classes. i.e. ArrayList is a subclass of List.
Only instances of subclasses of throwable can be used in conjunction with the throw keyword. In java all exceptions and errors are subclasses of throwable.
In Java, you use the final modifier to prevent a class from having any subclasses.
The top level class in Java is "Object." All other classes are subclasses of Object by default.
Hierarchical inheritance in Java allows multiple subclasses to inherit from a single parent class, promoting code reuse and reducing redundancy. Key advantages include: Code Reusability: Subclasses inherit common properties and methods from the parent class, reducing the need to write repetitive code. Maintainability: Changes made to the parent class are automatically reflected in all subclasses, simplifying code maintenance. Modularity: It enables a clear structure where common functionality is centralized, and specific features can be extended in subclasses. Efficiency: Inheritance minimizes code duplication, leading to more efficient and streamlined code.
You declare a method final in Java when you do not want any subclasses of your class to be able to override the method. I have also heard that this allows the Java compiler to make more intelligent decisions. For example, it supposedly allows Java to decide when to make a method inline. (Note that this is all unconfirmed)
Well, the Container extends Component, so ALL containers in Java are components. This includes classes like Panel, ScrollPane, Window, and JComponent. Plus all the various generations of subclasses of each of those containers.
You would want to use DateFormat when programming with Java. This command is an abstract class for date/time formatting subclasses. You can learn more at the documents section of the Oracle website.
The answer to this is related to the idea of inheritance in general - the idea of inheritance is that you define a common set of behaviors, that apply to all subclasses. Anything defined in the "Object" class is available to all classes you create. Look in the documentation for the description of the "Object" class, to see what methods are available in all Java classes.
They are Monotremes, marsipuals, eutherians.
Yes. Any class that does not provide implementation to all its methods as well as its parent class methods needs to be Abstract. The Java compiler would not successfully compile a class that does not do this.
Compile Time Polymorphism in Java is when you have the several methods with same name and different parameters and compiler has to decide how to select which method has to run based on the arguments hence the name Compile time polymorphism or method overloading.
If you do that, many definitions and later changes have to be done but in a single place, where they will affect the two (or more) subclasses.