diff --git a/src/main/java/io/mycat/backend/mysql/CharsetUtil.java b/src/main/java/io/mycat/backend/mysql/CharsetUtil.java
index fbdcbdaf4..cc7af98d6 100644
--- a/src/main/java/io/mycat/backend/mysql/CharsetUtil.java
+++ b/src/main/java/io/mycat/backend/mysql/CharsetUtil.java
@@ -26,7 +26,8 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.io.FileInputStream;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.*;
 
 /**
@@ -54,7 +55,7 @@ public class CharsetUtil {
                 + "index_to_charset.properties";
         Properties prop = new Properties();
         try {
-            prop.load(new FileInputStream(filePath));
+            prop.load(Files.newInputStream(Paths.get(filePath)));
             for (Object index : prop.keySet()){
                INDEX_TO_CHARSET.put(Integer.parseInt((String) index), prop.getProperty((String) index));
             }
diff --git a/src/main/java/io/mycat/backend/postgresql/utils/PacketUtils.java b/src/main/java/io/mycat/backend/postgresql/utils/PacketUtils.java
index 7ce4e483a..bdfc3b0f1 100644
--- a/src/main/java/io/mycat/backend/postgresql/utils/PacketUtils.java
+++ b/src/main/java/io/mycat/backend/postgresql/utils/PacketUtils.java
@@ -180,15 +180,15 @@ public static ByteBuffer makeStartUpPacket(String user, String database)
 		paramList.add(new String[] { "extra_float_digits", "3" });
 		paramList.add(new String[] { "application_name", appName });
 		String[][] params = paramList.toArray(new String[0][]);
-		StringBuilder details = new StringBuilder();
-		for (int i = 0; i < params.length; ++i) {
-			if (i != 0) {
-				details.append(", ");
-			}
-			details.append(params[i][0]);
-			details.append("=");
-			details.append(params[i][1]);
-		}
+		// StringBuilder details = new StringBuilder();
+		// for (int i = 0; i < params.length; ++i) {
+		// 	if (i != 0) {
+		// 		details.append(", ");
+		// 	}
+		// 	details.append(params[i][0]);
+		// 	details.append("=");
+		// 	details.append(params[i][1]);
+		// }
 
 		/*
 		 * Precalculate message length and encode params.
diff --git a/src/main/java/io/mycat/route/sequence/handler/IncrSequencePropHandler.java b/src/main/java/io/mycat/route/sequence/handler/IncrSequencePropHandler.java
index ae37c2532..d269f0e08 100644
--- a/src/main/java/io/mycat/route/sequence/handler/IncrSequencePropHandler.java
+++ b/src/main/java/io/mycat/route/sequence/handler/IncrSequencePropHandler.java
@@ -23,9 +23,9 @@
  */
 package io.mycat.route.sequence.handler;
 
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
 import java.io.OutputStream;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Properties;
@@ -61,7 +61,7 @@ public Map<String, String> getParaValMap(String prefixName) {
 		Map<String, String> valMap = new HashMap<String, String>();
 		Properties prop = new Properties();
 		try {
-			prop.load(new FileInputStream(filePath));
+			prop.load(Files.newInputStream(Paths.get(filePath)));
 			valMap.put(prefixName + KEY_HIS_NAME,
 					prop.getProperty(prefixName + KEY_HIS_NAME));
 			valMap.put(prefixName + KEY_MIN_NAME,
@@ -82,7 +82,7 @@ public Map<String, String> getParaValMap(String prefixName) {
 	public Boolean fetchNextPeriod(String prefixName) {
 		Properties props = new Properties();
 		try {
-			props.load(new FileInputStream(filePath));
+			props.load(Files.newInputStream(Paths.get(filePath)));
 			String minStr = props.getProperty(prefixName + KEY_MIN_NAME);
 			String maxStr = props.getProperty(prefixName + KEY_MAX_NAME);
 			String hisIDS = props.getProperty(prefixName + KEY_HIS_NAME);
@@ -95,7 +95,7 @@ public Boolean fetchNextPeriod(String prefixName) {
 			props.setProperty(prefixName + KEY_MAX_NAME,
 					(maxId - minId + maxId + 1) + "");
 			props.setProperty(prefixName + KEY_CUR_NAME, maxStr);
-			OutputStream fos = new FileOutputStream(filePath);
+			OutputStream fos = Files.newOutputStream(Paths.get(filePath));
 			props.store(fos, "");
 		} catch (Exception e) {
 			logger.error(e.getLocalizedMessage());
@@ -108,9 +108,9 @@ public Boolean fetchNextPeriod(String prefixName) {
 	public synchronized Boolean  updateCURIDVal(String prefixName, Long val) {
 		Properties props = new Properties();
 		try {
-			props.load(new FileInputStream(filePath));
+			props.load(Files.newInputStream(Paths.get(filePath)));
 			props.setProperty(prefixName + KEY_CUR_NAME, val.longValue() + "");
-			OutputStream fos = new FileOutputStream(filePath);
+			OutputStream fos = Files.newOutputStream(Paths.get(filePath));
 			props.store(fos, "");
 		} catch (Exception e) {
 			logger.error(e.getLocalizedMessage());
diff --git a/src/main/java/io/mycat/server/handler/ServerLoadDataInfileHandler.java b/src/main/java/io/mycat/server/handler/ServerLoadDataInfileHandler.java
index 6ea41af6b..641cb47be 100644
--- a/src/main/java/io/mycat/server/handler/ServerLoadDataInfileHandler.java
+++ b/src/main/java/io/mycat/server/handler/ServerLoadDataInfileHandler.java
@@ -774,14 +774,14 @@ private static void deleteFile(String dirPath) {
             return;
         }
         File[] fileList = fileDirToDel.listFiles();
-
-        for (int i = 0; i < fileList.length; i++) {
-            File file = fileList[i];
-            if (file.isFile() && file.exists()) {
-                boolean delete = file.delete();
-            } else if (file.isDirectory()) {
-                deleteFile(file.getAbsolutePath());
-                file.delete();
+        if (fileList != null) {
+            for (File file : fileList) {
+                if (file.isFile() && file.exists()) {
+                    file.delete();
+                } else if (file.isDirectory()) {
+                    deleteFile(file.getAbsolutePath());
+                    file.delete();
+                }
             }
         }
         fileDirToDel.delete();
diff --git a/src/main/java/io/mycat/util/dataMigrator/DataMigratorUtil.java b/src/main/java/io/mycat/util/dataMigrator/DataMigratorUtil.java
index 6a2089750..980cf7496 100644
--- a/src/main/java/io/mycat/util/dataMigrator/DataMigratorUtil.java
+++ b/src/main/java/io/mycat/util/dataMigrator/DataMigratorUtil.java
@@ -180,12 +180,14 @@ public static long countLine(File file) throws IOException{
     public static boolean deleteDir(File dir) {
         if (dir.isDirectory()) {
             String[] children = dir.list();
-            for (int i=0; i<children.length; i++) {
-                boolean success = deleteDir(new File(dir, children[i]));
-                if (!success) {
-                    return false;
-                }
-            }
+			if (children != null) {
+				for (String child : children) {
+					boolean success = deleteDir(new File(dir, child));
+					if (!success) {
+						return false;
+					}
+				}
+			}
         }
         // 目录此时为空，可以删除
         return dir.delete();