java singleton example

A singleton object (Singleton) is a common design pattern. In Java applications, singleton objects guarantee that only one instance of the object exists in a JVM. There are several benefits to this model:1, some classes are created more frequently, for some large objects, this is a lot of overhead.2, eliminate the new

the following code is thread-safe:Public class Singleton3 {private static volatile Singleton3 instance = null;Private Singleton3 () {}Public static Singleton3 getinstance () {if (instance = = null) {synchronzied (singleton3.class) {if (instance = = null) {instance = new Singleton3 (); } } }return instance; }}Singleton3 uses a locking mechanism to ensure that only one instance is created in a multithreaded environment, and that the two if judgments are used to improve efficiency. This

an element is an instance. */INSTANCE; /*** Test Method 1 *@return */ Public voiddosomething () {System.out.println ("# # # #测试方法 ######"); } /*** Test Method 2 *@return */ PublicString getsomething () {return"Got some content."; }}In the example above, enumsingleton.instance can obtain the desired instance, and the method of invoking the singleton can be EnumSingleotn.INSTANCE.doSomeThi

As an object's creation mode, Singleton mode ensures that a class has only one instance, and instantiates itself and provides this instance to the system as a whole.A singleton class can have only one instance.The Singleton class must create its own unique instance.The Singleton class must provide this instance to all

() { if (sing = = null) { synchronized (singleton.class) {if (sing = = null) {sing = new single ton (); }}} return sing;} }TestPackage com.lyz.design.singleton;/** * Testing class * @author Liuyazhuang * */public class Test {public static void main (Strin G[] args) { Singleton sing = Singleton.getinstance (); Singleton sing2 = Singleton.getinstance ();

system will regard it as garbage and will automatically destroy and Recycle resources. The next exploitation will be re-instantiated, which will lead to the loss of the shared singleton object status. 3. Applicable scenarios The Singleton mode can be considered in the following cases: (1) The system only needs one instance object. For example, the system require

This article address: http://www.cnblogs.com/archimedes/p/java-singleton-pattern.html, reprint please indicate source address. Single-Case mode Ensure that a class has only one instance and provides a global access point to access it. OverviewThe singleton pattern is a mature pattern of how to design a class that has only one instance of the cla

PackageCom.easygo.singleton;/*** Java Singleton There are two ways, a hungry man and lazy, a hungry man is loaded before the object is created, take precedence over the object, and the lazy is to call the object after the object creation method to create the object *, understand the JVM loading principle is clear, the true meaning of the singleton is a hungry man

role, it includes business methods that combine the creation of products with the functionality of the product itself. Many object-oriented languages, such as Java, C #, now run environments that provide automatic garbage collection, so if the instantiated shared object is not exploited for a long time, the system will consider it garbage, automatically destroy and reclaim the resources, and re-instantiate the next time it is exploited, which wi