代码优化，ConcurrentHashMap变量类型改为ConcurrentMap，避免因不同版本实现不同导致的兼容性问题；

doc/XXL-JOB官方文档.md

@@ -1503,6 +1503,7 @@ Tips: 历史版本(V1.3.x)目前已经Release至稳定版本, 进入维护阶段
 - 16、任务日志主键调整为long，防止海量日志情况下数据溢出；
 - 17、任务日志列表交互优化，操作按钮合并为分割按钮；
 - 18、HttpJobHandler优化，响应数据指定UTF-8格式，避免中文乱码；
+- 19、代码优化，ConcurrentHashMap变量类型改为ConcurrentMap，避免因不同版本实现不同导致的兼容性问题；
 
 
 ### 6.26 版本 v2.1.1 Release Notes[规划中]

xxl-job-admin/src/main/java/com/xxl/job/admin/core/conf/XxlJobScheduler.java

@@ -27,6 +27,7 @@ import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * @author xuxueli 2018-10-28 00:18:17
@@ -112,7 +113,7 @@ public class XxlJobScheduler implements InitializingBean, DisposableBean {
 
 
     // ---------------------- executor-client ----------------------
-    private static ConcurrentHashMap<String, ExecutorBiz> executorBizRepository = new ConcurrentHashMap<String, ExecutorBiz>();
+    private static ConcurrentMap<String, ExecutorBiz> executorBizRepository = new ConcurrentHashMap<String, ExecutorBiz>();
     public static ExecutorBiz getExecutorBiz(String address) throws Exception {
         // valid
         if (address==null || address.trim().length()==0) {

xxl-job-admin/src/main/java/com/xxl/job/admin/core/route/strategy/ExecutorRouteLFU.java

@@ -6,6 +6,7 @@ import com.xxl.job.core.biz.model.TriggerParam;
 
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * 单个JOB对应的每个执行器，使用频率最低的优先被选举
@@ -16,7 +17,7 @@ import java.util.concurrent.ConcurrentHashMap;
  */
 public class ExecutorRouteLFU extends ExecutorRouter {
 
-    private static ConcurrentHashMap<Integer, HashMap<String, Integer>> jobLfuMap = new ConcurrentHashMap<Integer, HashMap<String, Integer>>();
+    private static ConcurrentMap<Integer, HashMap<String, Integer>> jobLfuMap = new ConcurrentHashMap<Integer, HashMap<String, Integer>>();
     private static long CACHE_VALID_TIME = 0;
 
     public String route(int jobId, List<String> addressList) {

xxl-job-admin/src/main/java/com/xxl/job/admin/core/route/strategy/ExecutorRouteLRU.java

@@ -8,6 +8,7 @@ import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * 单个JOB对应的每个执行器，最久为使用的优先被选举
@@ -18,7 +19,7 @@ import java.util.concurrent.ConcurrentHashMap;
  */
 public class ExecutorRouteLRU extends ExecutorRouter {
 
-    private static ConcurrentHashMap<Integer, LinkedHashMap<String, String>> jobLRUMap = new ConcurrentHashMap<Integer, LinkedHashMap<String, String>>();
+    private static ConcurrentMap<Integer, LinkedHashMap<String, String>> jobLRUMap = new ConcurrentHashMap<Integer, LinkedHashMap<String, String>>();
     private static long CACHE_VALID_TIME = 0;
 
     public String route(int jobId, List<String> addressList) {

xxl-job-admin/src/main/java/com/xxl/job/admin/core/route/strategy/ExecutorRouteRound.java

@@ -7,13 +7,14 @@ import com.xxl.job.core.biz.model.TriggerParam;
 import java.util.List;
 import java.util.Random;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * Created by xuxueli on 17/3/10.
  */
 public class ExecutorRouteRound extends ExecutorRouter {
 
-    private static ConcurrentHashMap<Integer, Integer> routeCountEachJob = new ConcurrentHashMap<Integer, Integer>();
+    private static ConcurrentMap<Integer, Integer> routeCountEachJob = new ConcurrentHashMap<Integer, Integer>();
     private static long CACHE_VALID_TIME = 0;
     private static int count(int jobId) {
         // cache clear

xxl-job-admin/src/main/java/com/xxl/job/admin/core/thread/JobTriggerPoolHelper.java

@@ -49,7 +49,7 @@ public class JobTriggerPoolHelper {
 
     // job timeout count
     private volatile long minTim = System.currentTimeMillis()/60000;     // ms > min
-    private volatile ConcurrentHashMap<Integer, AtomicInteger> jobTimeoutCountMap = new ConcurrentHashMap<>();
+    private volatile ConcurrentMap<Integer, AtomicInteger> jobTimeoutCountMap = new ConcurrentHashMap<>();
 
 
     /**

xxl-job-core/src/main/java/com/xxl/job/core/executor/XxlJobExecutor.java

@@ -24,6 +24,7 @@ import org.slf4j.LoggerFactory;
 
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * Created by xuxueli on 2016/3/2 21:14.
@@ -223,7 +224,7 @@ public class XxlJobExecutor  {
 
 
     // ---------------------- job handler repository ----------------------
-    private static ConcurrentHashMap<String, IJobHandler> jobHandlerRepository = new ConcurrentHashMap<String, IJobHandler>();
+    private static ConcurrentMap<String, IJobHandler> jobHandlerRepository = new ConcurrentHashMap<String, IJobHandler>();
     public static IJobHandler registJobHandler(String name, IJobHandler jobHandler){
         logger.info(">>>>>>>>>>> xxl-job register jobhandler success, name:{}, jobHandler:{}", name, jobHandler);
         return jobHandlerRepository.put(name, jobHandler);
@@ -234,7 +235,7 @@ public class XxlJobExecutor  {
 
 
     // ---------------------- job thread repository ----------------------
-    private static ConcurrentHashMap<Integer, JobThread> jobThreadRepository = new ConcurrentHashMap<Integer, JobThread>();
+    private static ConcurrentMap<Integer, JobThread> jobThreadRepository = new ConcurrentHashMap<Integer, JobThread>();
     public static JobThread registJobThread(int jobId, IJobHandler handler, String removeOldReason){
         JobThread newJobThread = new JobThread(jobId, handler);
         newJobThread.start();

xxl-job-core/src/main/java/com/xxl/job/core/glue/GlueFactory.java

@@ -7,6 +7,7 @@ import groovy.lang.GroovyClassLoader;
 import java.math.BigInteger;
 import java.security.MessageDigest;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * glue factory, product class/object by name
@@ -33,7 +34,7 @@ public class GlueFactory {
 	 * groovy class loader
 	 */
 	private GroovyClassLoader groovyClassLoader = new GroovyClassLoader();
-	private ConcurrentHashMap<String, Class<?>> CLASS_CACHE = new ConcurrentHashMap<>();
+	private ConcurrentMap<String, Class<?>> CLASS_CACHE = new ConcurrentHashMap<>();
 
 	/**
 	 * load new instance, prototype