經典單例模式及測試

public class ClassicSingleton {private static ClassicSingleton instance=new ClassicSingleton();private ClassicSingleton() {}public static ClassicSingleton getInstance() {return instance;}}import java.util.logging.Logger;import junit.framework.Assert;import junit.framework.TestCase;public class SingletonTest extends TestCase {private ClassicSingleton sone=null;private ClassicSingleton stwo=null;private static Logger logger=Logger.getAnonymousLogger();public SingletonTest(String name) {super(name);}public void setUp() {logger.info("getting singleton...");sone=ClassicSingleton.getInstance();logger.info("...got singleton: "+sone);logger.info("getting singleton...");stwo=ClassicSingleton.getInstance();logger.info("...got singleton: "+stwo);}public void testUnique() {logger.info("checking singleton for equality");Assert.assertEquals(true, sone==stwo);}}