fix code

hutool-db/src/main/java/cn/hutool/db/dialect/DialectFactory.java

@@ -55,7 +55,7 @@ public class DialectFactory {
 	public final static String DRIVER_DM7 = "dm.jdbc.driver.DmDriver";
 	
 	private static Map<DataSource, Dialect> dialectPool = new ConcurrentHashMap<>();
-	private static Object lock = new Object();
+	private static final Object lock = new Object();
 
 	private DialectFactory() {
 	}

hutool-db/src/main/java/cn/hutool/db/dialect/DriverUtil.java

@@ -44,7 +44,7 @@ public class DriverUtil {
 		}
 		
 		Connection conn = null;
-		String driver = null;
+		String driver;
 		try {
 			try {
 				conn = ds.getConnection();
@@ -69,7 +69,7 @@ public class DriverUtil {
 	 * @throws DbRuntimeException SQL异常包装，获取元数据信息失败
 	 */
 	public static String identifyDriver(Connection conn) throws DbRuntimeException {
-		String driver = null;
+		String driver;
 		DatabaseMetaData meta;
 		try {
 			meta = conn.getMetaData();

hutool-db/src/main/java/cn/hutool/db/ds/GlobalDSFactory.java

@@ -12,7 +12,7 @@ import cn.hutool.log.StaticLog;
 public class GlobalDSFactory {
 
 	private static volatile DSFactory factory;
-	private static Object lock = new Object();
+	private static final Object lock = new Object();
 
 	/*
 	 * 设置在JVM关闭时关闭所有数据库连接

hutool-db/src/test/java/cn/hutool/db/ConcurentTest.java

@@ -37,7 +37,7 @@ public class ConcurentTest {
 			ThreadUtil.execute(new Runnable() {
 				@Override
 				public void run() {
-					List<Entity> find = null;
+					List<Entity> find;
 					try {
 						find = db.find(CollectionUtil.newArrayList("name AS name2"), Entity.create("user"), new EntityListHandler());
 					} catch (SQLException e) {

hutool-db/src/test/java/cn/hutool/db/MySQLTest.java

@@ -33,23 +33,19 @@ public class MySQLTest {
 	 * 事务测试<br>
 	 * 更新三条信息，低2条后抛出异常，正常情况下三条都应该不变
 	 * 
-	 * @throws SQLException
+	 * @throws SQLException SQL异常
 	 */
 	@Test(expected=SQLException.class)
 	@Ignore
 	public void txTest() throws SQLException {
-		Db.use("mysql").tx(new VoidFunc1<Db>() {
-			
-			@Override
-			public void call(Db db) throws Exception {
-				int update = db.update(Entity.create("user").set("text", "描述100"), Entity.create().set("id", 100));
-				db.update(Entity.create("user").set("text", "描述101"), Entity.create().set("id", 101));
-				if(1 == update) {
-					// 手动指定异常，然后测试回滚触发
-					throw new RuntimeException("Error");
-				}
-				db.update(Entity.create("user").set("text", "描述102"), Entity.create().set("id", 102));
+		Db.use("mysql").tx(db -> {
+			int update = db.update(Entity.create("user").set("text", "描述100"), Entity.create().set("id", 100));
+			db.update(Entity.create("user").set("text", "描述101"), Entity.create().set("id", 101));
+			if(1 == update) {
+				// 手动指定异常，然后测试回滚触发
+				throw new RuntimeException("Error");
 			}
+			db.update(Entity.create("user").set("text", "描述102"), Entity.create().set("id", 102));
 		});
 	}
 

hutool-db/src/test/java/cn/hutool/db/UpdateTest.java

@@ -1,14 +1,11 @@
 package cn.hutool.db;
 
-import java.sql.SQLException;
-
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Ignore;
 import org.junit.Test;
 
-import cn.hutool.db.Db;
-import cn.hutool.db.Entity;
+import java.sql.SQLException;
 
 public class UpdateTest {
 	
@@ -22,7 +19,7 @@ public class UpdateTest {
 	/**
 	 * 对更新做单元测试
 	 * 
-	 * @throws SQLException
+	 * @throws SQLException SQL异常
 	 */
 	@Test
 	@Ignore