diff --git a/xxl-job-admin/src/main/java/com/xxl/job/admin/controller/biz/JobGroupController.java b/xxl-job-admin/src/main/java/com/xxl/job/admin/controller/biz/JobGroupController.java
index b5ccfa88..906d1c24 100644
--- a/xxl-job-admin/src/main/java/com/xxl/job/admin/controller/biz/JobGroupController.java
+++ b/xxl-job-admin/src/main/java/com/xxl/job/admin/controller/biz/JobGroupController.java
@@ -8,6 +8,7 @@ import com.xxl.job.admin.mapper.XxlJobGroupMapper;
 import com.xxl.job.admin.mapper.XxlJobInfoMapper;
 import com.xxl.job.admin.mapper.XxlJobRegistryMapper;
 import com.xxl.job.core.constant.Const;
+import com.xxl.job.core.constant.RegistType;
 import com.xxl.sso.core.annotation.XxlSso;
 import com.xxl.tool.core.CollectionTool;
 import com.xxl.tool.core.StringTool;
@@ -155,7 +156,7 @@ public class JobGroupController {
 		List<XxlJobRegistry> list = xxlJobRegistryMapper.findAll(Const.DEAD_TIMEOUT, new Date());
 		if (CollectionTool.isNotEmpty(list)) {
 			for (XxlJobRegistry item: list) {
-				if (!Const.RegistType.EXECUTOR.name().equals(item.getRegistryGroup())) {
+				if (!RegistType.EXECUTOR.name().equals(item.getRegistryGroup())) {
 					continue;
 				}
 
diff --git a/xxl-job-admin/src/main/java/com/xxl/job/admin/scheduler/thread/JobRegistryHelper.java b/xxl-job-admin/src/main/java/com/xxl/job/admin/scheduler/thread/JobRegistryHelper.java
index 8493d893..b94882bf 100644
--- a/xxl-job-admin/src/main/java/com/xxl/job/admin/scheduler/thread/JobRegistryHelper.java
+++ b/xxl-job-admin/src/main/java/com/xxl/job/admin/scheduler/thread/JobRegistryHelper.java
@@ -3,6 +3,7 @@ package com.xxl.job.admin.scheduler.thread;
 import com.xxl.job.admin.model.XxlJobGroup;
 import com.xxl.job.admin.model.XxlJobRegistry;
 import com.xxl.job.admin.scheduler.config.XxlJobAdminBootstrap;
+import com.xxl.job.core.constant.RegistType;
 import com.xxl.job.core.openapi.model.RegistryRequest;
 import com.xxl.job.core.constant.Const;
 import com.xxl.tool.core.StringTool;
@@ -74,7 +75,7 @@ public class JobRegistryHelper {
 							List<XxlJobRegistry> list = XxlJobAdminBootstrap.getInstance().getXxlJobRegistryMapper().findAll(Const.DEAD_TIMEOUT, new Date());
 							if (list != null) {
 								for (XxlJobRegistry item: list) {
-									if (Const.RegistType.EXECUTOR.name().equals(item.getRegistryGroup())) {
+									if (RegistType.EXECUTOR.name().equals(item.getRegistryGroup())) {
 										String appname = item.getRegistryKey();
 										List<String> registryList = appAddressMap.get(appname);
 										if (registryList == null) {
diff --git a/xxl-job-admin/src/test/java/com/xxl/job/adminbiz/AdminBizTest.java b/xxl-job-admin/src/test/java/com/xxl/job/adminbiz/AdminBizTest.java
index bd3f66e9..e9e796db 100644
--- a/xxl-job-admin/src/test/java/com/xxl/job/adminbiz/AdminBizTest.java
+++ b/xxl-job-admin/src/test/java/com/xxl/job/adminbiz/AdminBizTest.java
@@ -1,5 +1,6 @@
 package com.xxl.job.adminbiz;
 
+import com.xxl.job.core.constant.RegistType;
 import com.xxl.job.core.openapi.AdminBiz;
 import com.xxl.job.core.openapi.model.HandleCallbackRequest;
 import com.xxl.job.core.openapi.model.RegistryRequest;
@@ -62,7 +63,7 @@ public class AdminBizTest {
     public void registry() throws Exception {
         AdminBiz adminBiz = buildClient();
 
-        RegistryRequest registryParam = new RegistryRequest(Const.RegistType.EXECUTOR.name(), "xxl-job-executor-example", "127.0.0.1:9999");
+        RegistryRequest registryParam = new RegistryRequest(RegistType.EXECUTOR.name(), "xxl-job-executor-example", "127.0.0.1:9999");
 
         Response<String> returnT = adminBiz.registry(registryParam);
         assertTrue(returnT.isSuccess());
@@ -77,7 +78,7 @@ public class AdminBizTest {
     public void registryRemove() throws Exception {
         AdminBiz adminBiz = buildClient();
 
-        RegistryRequest registryParam = new RegistryRequest(Const.RegistType.EXECUTOR.name(), "xxl-job-executor-example", "127.0.0.1:9999");
+        RegistryRequest registryParam = new RegistryRequest(RegistType.EXECUTOR.name(), "xxl-job-executor-example", "127.0.0.1:9999");
 
         Response<String> returnT = adminBiz.registryRemove(registryParam);
         assertTrue(returnT.isSuccess());
diff --git a/xxl-job-core/src/main/java/com/xxl/job/core/constant/Const.java b/xxl-job-core/src/main/java/com/xxl/job/core/constant/Const.java
index 031d66c3..0878fd90 100644
--- a/xxl-job-core/src/main/java/com/xxl/job/core/constant/Const.java
+++ b/xxl-job-core/src/main/java/com/xxl/job/core/constant/Const.java
@@ -25,9 +25,4 @@ public class Const {
      */
     public static final int DEAD_TIMEOUT = BEAT_TIMEOUT * 3;
 
-    /**
-     * registry type
-     */
-    public enum RegistType{ EXECUTOR, ADMIN }
-
 }
diff --git a/xxl-job-core/src/main/java/com/xxl/job/core/constant/RegistType.java b/xxl-job-core/src/main/java/com/xxl/job/core/constant/RegistType.java
new file mode 100644
index 00000000..84277203
--- /dev/null
+++ b/xxl-job-core/src/main/java/com/xxl/job/core/constant/RegistType.java
@@ -0,0 +1,18 @@
+package com.xxl.job.core.constant;
+
+/**
+ * Created by xuxueli on 17/5/9.
+ */
+public enum RegistType{
+
+    /**
+     * executor registry
+     */
+    EXECUTOR,
+
+    /**
+     * admin registry
+     */
+    ADMIN;
+
+}
\ No newline at end of file
diff --git a/xxl-job-core/src/main/java/com/xxl/job/core/executor/XxlJobExecutor.java b/xxl-job-core/src/main/java/com/xxl/job/core/executor/XxlJobExecutor.java
index 4a64b375..3b934811 100644
--- a/xxl-job-core/src/main/java/com/xxl/job/core/executor/XxlJobExecutor.java
+++ b/xxl-job-core/src/main/java/com/xxl/job/core/executor/XxlJobExecutor.java
@@ -94,7 +94,7 @@ public class XxlJobExecutor  {
         stopEmbedServer();
 
         // destroy jobThreadRepository
-        if (jobThreadRepository.size() > 0) {
+        if (!jobThreadRepository.isEmpty()) {
             for (Map.Entry<Integer, JobThread> item: jobThreadRepository.entrySet()) {
                 JobThread oldJobThread = removeJobThread(item.getKey(), "web container destroy and kill the job.");
                 // wait for job thread push result to callback queue
diff --git a/xxl-job-core/src/main/java/com/xxl/job/core/thread/ExecutorRegistryThread.java b/xxl-job-core/src/main/java/com/xxl/job/core/thread/ExecutorRegistryThread.java
index b998528b..251465ad 100644
--- a/xxl-job-core/src/main/java/com/xxl/job/core/thread/ExecutorRegistryThread.java
+++ b/xxl-job-core/src/main/java/com/xxl/job/core/thread/ExecutorRegistryThread.java
@@ -1,5 +1,6 @@
 package com.xxl.job.core.thread;
 
+import com.xxl.job.core.constant.RegistType;
 import com.xxl.job.core.openapi.AdminBiz;
 import com.xxl.job.core.openapi.model.RegistryRequest;
 import com.xxl.job.core.constant.Const;
@@ -42,7 +43,7 @@ public class ExecutorRegistryThread {
                 // registry
                 while (!toStop) {
                     try {
-                        RegistryRequest registryParam = new RegistryRequest(Const.RegistType.EXECUTOR.name(), appname, address);
+                        RegistryRequest registryParam = new RegistryRequest(RegistType.EXECUTOR.name(), appname, address);
                         for (AdminBiz adminBiz: XxlJobExecutor.getAdminBizList()) {
                             try {
                                 Response<String> registryResult = adminBiz.registry(registryParam);
@@ -78,7 +79,7 @@ public class ExecutorRegistryThread {
 
                 // registry remove
                 try {
-                    RegistryRequest registryParam = new RegistryRequest(Const.RegistType.EXECUTOR.name(), appname, address);
+                    RegistryRequest registryParam = new RegistryRequest(RegistType.EXECUTOR.name(), appname, address);
                     for (AdminBiz adminBiz: XxlJobExecutor.getAdminBizList()) {
                         try {
                             Response<String> registryResult = adminBiz.registryRemove(registryParam);