how to practice coding in java

Java improvements-understanding the application of String and String. intern () In practice, stringintern 1. First, String does not belong to eight basic data types. String is an object.Because the default value of an object is null, the default value of String is also null, but it is a special object and has some features that other objects do not have.2. Both new String () and new String ("") declare a ne

be recognized by the Computer. In fact, floating-point numbers are not suitable for precise calculations and are suitable for scientific calculations. float and double are used to denote numbers with a decimal point, and these numbers are stored in the form of scientific notation. When a number such as 50.534, converted to scientific notation in the form of 5.053e1, its decimal point moved to a new position (that is, Floating) visible, floating point is used for scientific calculation, for accu

" 0000 system.out.println (integer.tohexstring ( -128)); //ffffff80 //(-128 0xFF) Complement: 1111 1111 1111 1111 1111 1111" 0000 0000 0000 0000 0000 0000 0000 1111 1111 = 0000 0000 0000 0000 0000 0000" 0000 system.out.println (integer.tohexstring ( -128 0xFF)); //00000080 //byte byte_128 = (byte) -128 (---128 complement reserved last 8--0000) //byte_128 complement: 0000 //byte_128:1111 1111 (symbol bit invariant remaining bit reversed) //byte_128

into the buffer or writes to the operating system.Asynchronous Io:aio-based on the idea of event-driven, implemented by Proactor mode. When reading and writing, just call the API's read or write method directly, both of which are asynchronous. When a stream is readable, the operating system streams the readable buffer into the Read method and notifies the application. When the operating system writes the stream that is passed by the Write method, the operating system proactively notifies the ap

Introduction to Java NIO (iii) from theory to practice: using NIO to read and writeGuibin.beijing@gmail.com OverviewReading and writing are the most basic IO processing. Reading from a Channel is very simple. We only need to create a Buffer and then require the Channel to read data to the Buffer. Writing is also very simple. You also need to create a Buffer to fill the data to be written into the Buffer, an

: Reflection function name * @ return ReflectionMethod obj: callback object */protected static function getPrivateMethod ($ strMethodName) {$ objReflectClass = new ReflectionClass (self: CLASS_NAME); $ method = $ objReflectClass-> getMethod ($ strMethodName ); $ method-> setAccessible (true); return $ method ;} The following is an example of calling another type of private method using reflection in java. We know that

LinkedList, because linkedlist to move the pointer.Add and remove,linkedlist are the dominant for new and deleted operations because ArrayList is moving the data.ArrayList space waste is mainly reflected in the end of the list to reserve a certain amount of space, while the linkedlist of the space cost is reflected in its every element needs to consume considerable space.ArrayList is based on an array implementation.LinkedList is based on a linked list implementation. This article is from the

Java.lang.instrument.instrumentation;import Org.apache.bcel.constants;import Org.apache.bcel.classfile.classparser;import Org.apache.bcel.classfile.javaclass;import Org.apache.bcel.classfile.method;import Org.apache.bcel.generic.classgen;import Org.apache.bcel.generic.constantpoolgen;import Org.apache.bcel.generic.instructionconstants;import Org.apache.bcel.generic.instructionfactory;import Org.apache.bcel.generic.instructionlist;import Org.apache.bcel.generic.methodgen;import Org.apache.bcel.g

version of the problem, may use Maven way, actually now can also be directly used in Java engineering development methods, see their favorite. In addition, the latest API development is simpler and supposedly more efficient, so .... Groping all is tears. Hope this article can make everyone less detours. 1 Maven way to establish the project (feasible, personally do not recommend, because the workplace without extranet) ----------specific installation

The practice of Java NIO Communication framework in telecom fieldThis article is wrong, Huawei Telecom Software V1 version of the logic frame composition and Huawei Telecom software V2 MVC version of the logical framework diagram two map is the same picture Another: I think the author encountered in this article due to synchronization IO caused by the history of the problem is more of the architecture pro

[Java concurrent programming practice] ----- "J. U. C": Exchanger We have introduced three synchronization auxiliary classes: CyclicBarrier, Barrier, and Phaser. This blog introduces the last one: Exchanger. Jdk api is introduced as follows: synchronization points of threads that can pair and exchange elements in a pair. Each thread presents a method on the entry to the exchange method, matches with the par

-sonatype?hsCtaTracking=920dd7b5-7ef3-47fe-9600-10fecad8aa32% 7cf59d5f10-099f-4c66-a622-0254373f4a92 Installation, decompression, if you need to modify the port number and other information, you can modify the file \nexus-3.13.0-01\etc\nexus-default.properties Start command go to \nexus-3.13.0-01\bin, Nexus/run can view boot log Use: http://books.sonatype.com/nexus-book/reference3/index.html Adding a publishing node to the POMModify settings.xml Add server account password infor

In the Java Concurrency Programming practice, 4.4 mentions the method of locking the client. This is a validation example, but it is not good to write, but you can see the result. Packagecom.blackbread.test;Importjava.util.ArrayList;Importjava.util.Collections;Importjava.util.List;ImportJava.util.concurrent.ExecutorService;Importjava.util.concurrent.Executors; Public classGoodlisthelper { PubliclistNewA

Plan to write a "Java Concurrent basic Practice" series, counted as my Java concurrency Learning and practice of a simple summary. This is the first of the series that describes the easiest way to quit a concurrent task. After a concurrent task is started, do not expect it to always perform. Due to time constraints, r

(); }/** * * */PublicvoidSendfinish () {sendfinish =True; }/** * * */PublicvoidRelease () {System.Out.println ("release!");if (BW! =Null) {Try{Bw.close ();}Catch(IOException e) {//TODO Print log.} }//In fact, using queue = null is enough.if (Queue! =Null) {queue.clear (); queue =Null; } }/** * * */PublicvoidSendmsg (String text) {if (Text! =Null !Text.isempty ()) {queue.add (text);}}PublicStaticvoidMain (string[] args) {Countdownlatch latch =New Countdownlatch (1); Asynchandler handler =NewAsyn

Apriori condition (precondition): Some methods contain a priori condition based on a state. For example, you cannot remove an element from an empty queue, and the queue must be in a non-empty state before the element is deleted. The operation of a state-based priori condition becomes a dependent state operation. In a single thread, if an operation fails to meet a priori condition, it can only fail, but in a concurrent program a priori condition may become true due to an operation performed b

1 Use the tool (Code->reformate code) in idea to reformat the code below, and then look at the Code menu to find a feature that feels best for you. Submit, plus your own study number watermark.public class Codestandard {public static void main (String [] args) {StringBuffer buffer = new StringBuffer (); Buffer.append ( ' S '); Buffer.append ("Tringbuffer"); System.out.println (Buffer.charat (1)); System.out.println (Buffer.capacity ()); System.out.println (Buffer.indexof ("Tring")); System.out.p

on hash The entire allocation process is artificially mastered, and when certain requests must be assigned to the specified server, the modifications are simpler Disadvantages: Large number of coding needs rigorous testing Need to proactively maintain a routing table, storage is an issue to consider When the request volume is large, the routing table capacity will increase, you can consider to deposit in Redis The above is my underst

"); System.out.println ("usage:democlient [Host=localhost] [port=9090]"); System.out.println ("This demo assumes you has a table called \" Example\ "with a column family called \" family1\ "); String host = "192.168.58.101"; int port = 9090; Use passed in arguments instead of defaults if (args.length >= 1) {host = Args[0]; } if (Args.length >= 2) {port = Integer.parseint (args[1]); } int timeout = 10000; Boolean framed = false; Ttransport transport = new Tsocket (host

input. Each line have the number of all possible ways to distribute D CDs among N nephews.Sample Input1 203 100 0Sample Output159049Ask N^d. Large number, Java, the large number of C + + template is really no love, decisive JAVA.Import java.io.*;import java.math.*;import java.util.*;p ublic class Main {public static void Main (string[] arges) { C1/>biginteger N; int D; Scanner cin = new Scanner (system.in); while (Cin.hasnext ())