fix ArthasAgent NullPointerException. #1546

arthas-agent-attach/src/main/java/com/taobao/arthas/agent/attach/ArthasAgent.java

@@ -45,7 +45,10 @@ public class ArthasAgent {
 
     public ArthasAgent(Map<String, String> configMap, String arthasHome, boolean slientInit,
             Instrumentation instrumentation) {
-        this.configMap = configMap;
+        if (configMap != null) {
+            this.configMap = configMap;
+        }
+
         this.arthasHome = arthasHome;
         this.slientInit = slientInit;
         this.instrumentation = instrumentation;

core/src/main/java/com/taobao/arthas/core/server/ArthasBootstrap.java

@@ -189,7 +189,10 @@ public class ArthasBootstrap {
          * https://github.com/alibaba/arthas/issues/986
          * </pre>
          */
-        Map<String, String> copyMap = new HashMap<String, String>(argsMap);
+        Map<String, String> copyMap = new HashMap<String, String>();
+        if (argsMap != null) {
+            copyMap.putAll(argsMap);
+        }
         // 添加 arthas.home
         if (!copyMap.containsKey(ARTHAS_HOME_PROPERTY)) {
             copyMap.put(ARTHAS_HOME_PROPERTY, arthasHome());