java class extends

{ System.out.println ("Class B is initialized");//output }}class A extends B { static { System.out.println ("Class A is initialized"); Do not output }}public class Superclasstest {public static void Main (string[] ar

Java is a single inheritance language, but in the inheritance relationship of subclasses, there are cases where the parent class and the interface have the same method. Let's take a step-by-step validation: 1. Subclass inherits the parent class, implements the interface, and the parent class and interface have the sa

Java Abstract class and java Abstract What is an abstract class? This name is very abstract. The first time I heard this name, it may be blocked. However, as the old man said, all anti-sprees are paper tigers, and the concept of dressing x is also a paper tiger. Well, we have already put down on it strategically. Now

Class loading is one of the most powerful mechanisms provided by the Java language. Although class loading is not a hot topic, all programmers should understand its working mechanism and understand how to make it meet our needs. This effectively saves our coding time and frees us from the work of continuously debugging classnotfoundexception and classcastexceptio

FinalKeyword as a modifier1. You can modify classes, functions, variables2. A class that is final modified cannot be inheritedIn order to avoid being inherited, quilt-like replication function.3. Final modification of the method, can not be replicated4. The final modified variable is a constant that can be assigned only once, either to modify the member variable or to modify the local variable. As constants: The writing specification for constants: Al

Java basics 9-abstract class, java-AbstractJava basics 9-abstract class 1. Introduction to abstract classes /*Abstract class:Abstract: general, fuzzy, and incomprehensible! Not specific. Features:1. MethodOnly declarations are not implementedThis method isAbstract Method, Need to beAbstract.Abstract methods must be de

Public class Animal {Public static void Main (string[] args) {Animal Animal = new Cat ();Animal.voice ();Drinkwater (animal); Call a static method, passing in a subclass object referenced by the parent class }String str;Public void Voice () {System.out.println ("Ordinary animal cries!") "); }Public static void Drinkwater (Animal Animal) {//static method, passed in Animal parent

This blog post focuses on the process of loading a class from a Java virtual machine, some of which are referred to in-depth understanding of Java virtual machines. In order to avoid the tedious explanation, in order to let the reader after reading this article can thoroughly understand the class loading process, first

1 U2 Interfaces_count 1 U2 Interfaces Interfaces_count U2 Fields_count 1 Field_info Fields Fields_count U2 Methods_count 1 Method_info Methods Methods_count U2 Attribute_count 1 Attribute_info Attributes Attributes_count The version number of the magic number and

JAVA class and object ------ inheritance, java ------ inheritance Understanding: inheritance can be understood as an object's process of obtaining attributes. If Class A is the parent class of Class B, and

Common Java class libraries-Observer design patterns (Observable class Observer Interface) and observableobserver Link: http://www.2cto.com/kf/201310/253013.html To implement the Observer mode, you must rely on the Observable class and Observer interface provided in the java