java practice exam

Similar to the multi-tasking scenario of a Web server, it is not possible to use only one thread to provide services externally. This way, efficiency and throughput are too low.However, it is not possible to create a thread with a single request because the cost of creating the thread is very high and the number of threads that the system can create is limited.So the executor appeared.The meaning of executor frame thread poolThread creation too little wasted server resources, in addition to the

To kneel and beg for a simple way ......... .....Rules.1. This Council once 10 points plus 2 pitches in the back2 This council complements 10 points plus 1 pitches in the back3 this council 2 times less than 10 points that's all.10th round in any case must first cast 2 times 2 times more than 10 points to increase the investment 1 timesOut of 300Package com.lovo;/** * Bowling Credit Program * @author Abe */import Java.util.scanner;public class Bowling {public static void main (STR Ing[] args) {S

When the main thread in a single-threaded application throws an unhandled exception, as the console prints the stack trace (also because the program stops), you are likely to notice. However, in multithreaded applications, especially in applications that run as servers and are not connected to the console, thread death can become a less compelling event, causing local systems to fail, resulting in chaotic application behavior. In the Java theory and

such as on are also called subscriptions published to the channel (using the Publish and subscribe commands), in addition to subscription publishing to mode (using Psubscribe to subscribe to a pattern) Subscribe to all CCTV channels 127.0.0.1:6379> psubscribe cctv* Reading messages ... (Press Ctrl-c to quit) 1) "Psubscribe" 2) "cctv*" 3) (integer) 1 When a CCTV1 message is still pushed first, the client receives it normally. The implementation of Pub/sub in

Java Practice question: rabbit problem This question is also called the Fibonacci sequence (Fabonacci), the first person to study the series is the Leonardo of Pisa (also known as the Fibonacci), which he used to describe the number of rabbits growing. The first month there are a couple of newborn rabbits. After the second month, they can have babies. Every month a pair of fertile rabbits will be born, and

EasyDB-0.1Instructions for useI practiced the use of aJAVAOpen-Source small framework for database interaction. 2015-2-25Welcome everyone to download the use, upgrade.Operation Steps:1. Create a new file in the src directory jdbc.porperties file (file name and location cannot be changed)2. Class Description:3.JavaBean must be a strict standard JavaBean,theset method format must follow the setxxxx () {} style. Otherwise not supported: Http://files.cnblogs.com/files/litaiqing/EasyDB-0.1.zipEasydb-

1972-05-05 Assistant computer Department831 Liu Bing 1977-08-14 teaching assistant, Department of Electronic Engineering1. Query the sname, Ssex, and class columns of all records in the student table.2, the inquiry teacher all units namely does not duplicate depart column.3. Query all records of student table.4. Query all records from 60 to 80 of the scores in the score table.5. Check the record of 85, 86 or 88 in the score table.6, inquires the student table "95031" class or the sex is "the fe

Recently made a technical blog site, organized a study of the Java process to do examples and small projects, are placed on the site to provide download, there are examples of beginners, there are Java Web examples, as well as my university during the graduation design source, can be downloaded.Address: micro-Child blog-java Novice

Many Java™ language methods, such as Thread.sleep() and Object.wait() , can be thrown InterruptedException . You cannot ignore this exception because it is a check exception (checked exception). But what should be done about it? In Java theory and practice this month, the concurrency expert Brian Goetz will explain Interruptedexception's meaning, why it throws in

Java Theory and Practice: using Volatile variables correctly Volatile variables in the Java language can be thought of as "light", and synchronized synchronized volatile variables require less coding and run-time overhead than blocks, but only part of the functionality that they can implement synchronized . This article describes several patterns for using vo

://gitee.com/BESTI-IS-JAVA-2018/20165325.git4. Related refactoring shortcut key content summary:快速调取一个方法：Ctrl+Alt+M快速提取常量：Ctrl+Alt+C 快速提取变量：Ctrl+Alt+V快速提取成员变量：Ctrl+Alt+F快速更改类名：Shift+F6Agile development and XP practice four experimental requirements: in pairs to complete the Java cryptography related content learning, combined with refactoring, git, code standards

Final keywords are often misused-they are used excessively when declaring classes and methods, but are not used enough when declaring instance fields. This month, Java practitioner Brian Goetz explored some useful final. Like in its cousin-CconstThe same keyword, according to the context,finalIt indicates different things.finalKeywords can be applied to classes, methods, or fields. When applied to a class, it means that the class can no longer genera

The new lock class improves synchronicity--but it can't be abandoned right now. SynchronizedJDK 5.0 provides a number of new and effective options for developers to develop high-performance concurrent applications. For example, a java.util.concurrent.lock class in the ReentrantLock Java language is synchronized replaced with the same memory semantics, the same lock, but with better performance under race conditions, and there are synchronized other fe

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