core java volume ii

) proxy.newproxyinstance ( fly.getclass (). getClassLoader (), new class[] {flyable.class}, new Objecthandler (fly)); } public static void Main (string[] args) { flyable fly = Flyfactory.getflayimpl (); Fly.addwing (null); System.out.println (Fly.fly ());} }Core Class Description:The JDK provides a class named Proxy.newproxyinstance (All-in-one). Where is the first parameter for the loader th

Exception handlingThe parent class in the exception structure Throwable class, its Exceptionlei class and the error class. What we can catch in the program is the subclass exception of exception.Error at System level: Error in Java Runtime Environment, we are not controllable.Exception is a program-level error: we can control it. 1) catch Exceptions in two ways: one is to add Try-catch to catch the exception, and the other is to declare the exceptio

the source file. If you do not place the package statement in the source file, the class in the source file is placed in a default packet.The compiler does not check the directory structure when compiling the source files. So as long as the source file is not dependent on other packages, the compilation error does not occur even if it is not in the declared package, but a run error occurs because the virtual machine cannot find the file.Package Scope:The parts marked as public can be used on an

Java core programming-byte stream of IO stream (2), javaio 1. byte stream A 1.1-byte stream is a stream that operates byte. Byte streams can operate on any data, such as media data, music, movies, and images. Of course, they can also operate on characters. Byte stream is based on byte stream, we know that a byte is 8 binary bits, a byte corresponds to an English character in the UTF-8, people found that usi

Running a Java program in a Web page is called an applet.ReflectionThis feature is used extensively in JavaBeans, which is the architecture of Java components.A program capable of analyzing classes is called reflection (reflective). The function of the reflection mechanism and its powerful, as can be seen below, the reflection mechanism can be used to: Ability to analyze classes in the run View obj

)Analysis: When a class is loaded, from the parent class to the subclass, from top to bottom, execute the static code block, and then execute the main function , if there is a statement of the new object, The construction code block and constructor of the binding are executed. Note: static code blocks have and execute only once14. What is the result of the following code?public class a{public static void Main (string[] args) {String str;System.out.println ("" + str);}}Analysis: The above code w

block first, and the post constructor)Parse: When a class is loaded and finished, from the parent class to the child class. From top to bottom. Run the static code block first, then run the main function , and if there is a statement for the new object, run the bound construction code block and constructor. Note: static code blocks are available and run only once14. What is the execution result of the following code?public class a{public static void Main (string[] args) {String str;System.out.

I recently concluded that I have not improved my skills. I am ready to start training. Write down this and give myself a goal. The core APIs of Java are very large, which makes it very convenient for developers. Many people often comment that java makes programmers stupid.However, I think some content must be mastered. Otherwise, it will be difficult to use

. 245 page71 Video 8.6 Viewer mode for linkage Scenarios 8.4.3 page No. 25172 Video 8.7 Applying a dependency reversal principle can reduce the range of changes affected 8.5.1 No. 254 page73 Video 8.8 A single responsibility principle that can keep classes as stable as possible 8.5.2 No. 256 page74 Video 8.9 The Richter replacement principle to follow when inheriting 8.5.3 No. 257 page75 Video 8.10 Optimizing inherited usage scenarios by using the synthetic Multiplexing Principle page No. 261 of

time.Look directly at an example:public class program{static void Main (string[] args) { UI layer = new UI (); Layer. Setdataaccessor (New Xmldataaccessor ()); Layer. Do (); }} class ui{dataaccessor m_accessor; public void Setdataaccessor (Dataaccessor accessor) {m_accessor = accessor;} public void does () { m_accessor. GetUser (); }} interface dataaccessor{void GetUser (); void RegisterUser ();} class xmldataaccessor:dataaccessor{public void GetUser () {} public void RegisterUser () {}}Th

The ArrayList of the Core Java thing.　　High-rise ground, Java Foundation to pick up. Today, I looked at the core Java from the basic point to find a little bit to share.First of all, the professional-level Lucky Star actor---employee Class (PS: I am focused on Lucky Star 30)

First, to talk about final, finally, finalize the difference.Final modifier (keyword) If a class is declared final, it means that it can no longer derive a new subclass and cannot be inherited as a parent class. Therefore, a class cannot be declared abstract and declared final. Declaring variables or methods as final ensures that they are not changed in use. A variable declared as final must be given an initial value at the time of declaration, and can only be read in subsequent references and c

Core Java- concept Chapter If you need to know which Unicode characters belong to the Java alphabet, you can use the Javaidentifierstart and Javaidentifierpart methods of the Charactor class to detect Const is a reserved word for Java, but it is not currently used An integer that is 0 apart will produce an exception

(); to } +}Exception in thread "main" Java.lang.RuntimeException:call aAt Com.eyu.onequeue.testexception.a (testexception.java:12)At Com.eyu.onequeue.TestException.demo (testexception.java:30)At Com.eyu.onequeue.TestException.main (testexception.java:5)caused By:java.lang.RuntimeException:call bAt com.eyu.onequeue.testexception.b (testexception.java:21)At Com.eyu.onequeue.testexception.a (testexception.java:10)... 2 morecaused By:java.lang.RuntimeException:call CAt COM.EYU.ONEQUEUE.TESTEXCE

main element between, child elements and child elements between the space also forget. If you only want to get child elements, you can do this:NodeList children = Root.getchildnodes ();for (int i=0;iNode child = Children.item (i);if (child instanceof Element) {Element childelement = (element) child;...}}This processing is still very troublesome, this is why the subsequent introduction of the DTD, the DTD can be used to standardize the content of XML, reduce some unnecessary validation process.L

Nio:new IOStarting with JDK1.4, the new IO, which can map a disk file into memory, we then read the data in memory.stored in the Java.nio packageJava NIO (new IO) is a new IO API introduced by the Java1.4 version, which can replace the standard Java IO API, which is now primarily used in servers, and is sufficient for us to write code that still uses traditional IO.Java NiO provides a different way of working with iOS than standard IO:Channels and buf

This section begins the Java Multithreaded Programming learning, the basic concepts of the operating system, processes, threads are no longer mentioned, just understand Java for multithreaded programming support.First, inherit the thread class to create threadsThe Java language uses the thread class to represent threads, and classes that represent threads can imp

Thread pool is a key point to be mastered in multi-threaded learning.The cost of starting a new thread is higher because it involves interacting with the operating system. In this scenario, using the thread pool can improve performance, especially if you need to consider using a thread pool when you want to create a lot of short-lived threads in your program.I. How do I create a thread pool??Before Java5, the thread pool was developed manually, and from Java5 onwards,

have different implementationsMethod definitions in Java--------------------------1) A method allows the presence of multiple modifiers, with no order of precedence between multiple modifiers2) The return type is located after the modifier, and a method must have a return typeFor methods that do not return a value, the return type is void3) When there is a return value in the method, each branch in the method is required to have a return to ensure th

Why is the use of volatile lower than the cost of synchronization? The cost of synchronization is mainly determined by its coverage, and if you can reduce the coverage of synchronization, you can significantly improve program performance. And volatile's coverage is variable-level only. Therefore, its synchronization cost is very low. What is the volatile principle? Volatile's semantics, in fact, is to tell the processor, do not put me into working memory, please directly in main memory opera