Java

　　This article tells the four characteristics (ACID) of transactions in the database, and will explain the isolation level of the transaction in detail.If a database claims to support transactional operations, then the database must have the

1. Introduction1.1 History of concurrencyCause: Resource utilization, fairness, convenience1.2 Advantages of threading1.2.1 Powerful multi-processor capabilitiesThe simplicity of 1.2.2 ModelingSimplified processing of 1.2.3 asynchronous events1.2.4

Threads and processes: The operating system performs multitasking, each task is a process, the process performs multitasking, each task is a thread, and contains a relationship.One, multi-threaded creation and startup:1. Inherit thread: Override the

1. The simplest memory overflowpublic class Heapoom { heapoom[] testlist= new heapoom[100000]; public static void Main (string[] args) { list list= new arraylist (); while (true) { list.add (new Heapoom ());}}} 　　2,

Baidu Encyclopedia: Merge Sort (merge-sort) is an effective sorting algorithm based on merging operation, which is a very typical application using divide-and-conquer method (Divide and Conquer). The ordered Subsequence is merged to obtain a fully

1. Thread pool ConceptThe thread pool, in fact, is a container that accommodates multiple threads, where threads can be reused, eliminating the need to create thread objects frequently and consuming excessive resources without having to create

Maintaining Gmt_create and gmt_modified fields in SQLDatabase tables generally need to have gmt_create and gmt_modified two fields, but this two field does not need to be maintained in the application layer, even in the entity class, only in the SQL

Using the encapsulated Mailutils tool, do the Send mail test:1/*2* Test Mailutils3* The underlying dependency is Javamail:activation.jar,mail.jar4*/5PublicClassmailutilstest {6@Test7PublicvoidSend () throws Messagingexception, ioexception{8 Session

Citation: https://www.cnblogs.com/hongten/p/hongten_java_sleep_wait.htmlFor the Sleep () method, we first need to know that the method belongs to the thread class. The wait () method is part of the object class.The sleep () method causes the program

Java Basics 30 Q 1. Object-oriented and process-oriented differentiation-oriented processesAdvantages: The performance is higher than object-oriented, because the class calls need to instantiate, the cost is relatively large, compared to consume

1. The difference between run () and start ()2. Basic thread properties and methods ID: An incremented integer, one for each thread created Name Priority: from 1 to 10, the default is 5, which is mapped to the priority in the system.

Git Learning reference: HTTPS://GIT-SCM.COM/BOOK/ZH/V2Common commands git initInitialize Project git add *.javaAdd files to git version control (all files for. java suffix)There are three states of Git, commited (committed), modified (modified)

Java1.5 the introduction of meta-annotations, now the most active open source community spring began to highly respected, originally familiar with the various XML configuration, at a glance, suddenly disappeared, a variety of annotations,

The contains () method and the Remove () method in collection.Boolean contains (Object O), which is used to determine whether an element is contained in the collection, if it contains, returns true, and does not contain a return of false. Combine

Suppose you now have a function f (x) = a + XThis function is not complete, such as f (1) = a + 1You have one question: How much is a?There are two ways to answer this questionThe first is called "Dynamic Scope", and the value of a is determined by

First, the conclusion.Subclass constructor, parent class constructor, variable initializationPaste Code Animcal.java Parent classpublic class Animal{ private static int index = 0; private static String getStaticName() { String name =

Java implements Excel data export:Currently, there are two Jakarta poi and Java Excel Technologies that are commonly used to implement Java Import and export Excel.Jakarta POI is a set of Java APIs for accessing Microsoft format documents. Jakarta

a whole morning, I sat in the cold Autumn cold air, looking out of the window gray sky, old buildings, there is a locust tree green still exist, not fallen leaves, let the good times and time in the lonely cold world slowly lost and barren. Winter

Tool categorypublic class Ben2xmlutil {/*** Convert objects directly to XML output of type string** @param obj* @return*/public static String converttoxml (Object obj) {Create an output streamStringWriter SW = new StringWriter ();try {Using the

Why the decorator pattern appearsTo enhance the functionality of a class, you can create a new class to inherit from this class, which solves the problem, but if you add more functionality, the hierarchy of inheritance becomes deeper, causing the