Java

First, IntroductionBased on the following two principles in the object-oriented five principles, we should consider using interfaces and abstract classes more than one:Richter Substitution principle: Subclasses can replace the parent class by

Public voidtestexception () {int a[] = {1,2,3};int q = 0;try{for (int i=0;ioutputarithmeticexceptionfinally *        Key points1:AlthoughArithmeticExceptioninherit fromException, but when it happensArithmeticExceptionException *                      

1, although the array provides a good function to save a set of variables, but because of the problem of the array congenital-fixed length, it is decided that the array in the actual work is not so commonly used, but in the written examination like

A simple point about a servlet is actually a middle-tier interface that handles client requests on a Web server.Second, about thread 1, general integration runnable or THREAD2, thread synchronization using synchronizedThird, about the exception Java

I. OverviewCommand modeSecond, the Code1.client.java1 Public class Client {2 3 Public void request (server server) {4 server.addcommand (new Textcommand ()); 5 Server.addcommand (new Imagecommand ()); 6

/** Demand: * Bank has a vault * There are two depositors, each saving 300 yuan. Save 100, save three times * * This is a thread problem, * * We should look at the following three ways to find the problem * 1. Identify which code is multithreaded to

I. Overview1. Target: Modify proxy to proxy any interface and any of its methods2. Ideas:(1) Proxy arbitrary interface: newproxyinstance (Class interfze) to pass the interface type as parameter to Proxy(2) Proxy arbitrary method: Use

Garbage collection (Garbage Collection, GC) is one of the important features of Java that differs from C and C + +.He helps Java automatically empty objects that are no longer used in the heap.Because there is no need to manually free up memory,

Reprint Please specify source: http://blog.csdn.net/l1028386804/article/details/46583279public class helloworldwww{public static void Main (String args[]) { int num;//Declare an integer variable num num =

Source: Java string encryption and decryptionSource code: Http://www.zuidaima.com/share/1557602896464896.htmThis period of time is exactly the need to encrypt the password in the system, but also to be able to decrypt, support the custom key. Now

I. Overview1. Application of Bridge Mode: (1) two dimension extension (2) permutation combinationSecond, the Code1.gift.java1 Public class Gift {23 protected Giftimpl Giftimpl; 4 }2.giftimpl.java1 Public class Giftimpl {23 }3.warmgift.java1

Ant build Java projectwe create the HelloWorld project, which sends the source file. Java to SRC, compiled with bytecode. Class is placed in the bin and the corresponding jar package is placed in the EXE directory. start by using the command line to

First, Servletcontextlistener Method Summary  void contextDestroyed(ServletContextEvent sce)Receives notification that the ServletContext was about to being shut down.  void

Get system Current time using: Java.util.Date class, and this date is constructed as follows:Non-parametric construction: public Date ()Constructive: public date (long date)First Instance:import java.util.*; Public class Datedemo {

Public Static void Main (string[] args) { String pattern = "Yyyy-mm-dd HH:mm:ss"; SimpleDateFormat format = new SimpleDateFormat (pattern); String curdate = Format.format (New Date ()); System.out.println (curdate); } Letters

Member variables and local variables, member variables local variables In java, variables can be divided into two categories based on their locations: member variables and local variables. Member variables are defined in the class, including: 1.

Springmvc interceptor usage summary, springmvc Summary /******The role of the Interceptor: * Each request can be intercepted before it reaches the Controller or before each response arrives at the view.* 1. Global log (who submitted the

Zorka source code interpretation: Beanshell and zorka interaction implementation, zorkabeanshell 1. beanshell basic knowledgeCall BeanShell from an applicationCreate a BeanShell interpreter (interpreter)Run the eval () and source () commands to

Android and androidsdk In actual development, the LayoutInflater class is very useful, and its function is similar to findViewById (). The difference is that LayoutInflater is used to find and instantiate xml layout files under res/layout/, while

Spring util namespace and util namespace In the spring configuration file, the util namespace is similar to the java. util package class. The util namespace provides collection-related configurations. before using the namespace, import the util