fix the problem of potential NPE in ACL plain

acl/src/main/java/org/apache/rocketmq/acl/plain/PlainPermissionManager.java

@@ -89,7 +89,7 @@ public class PlainPermissionManager {
             List<PlainAccessConfig> plainAccessConfigList = accounts.toJavaList(PlainAccessConfig.class);
             for (PlainAccessConfig plainAccessConfig : plainAccessConfigList) {
                 PlainAccessResource plainAccessResource = buildPlainAccessResource(plainAccessConfig);
-                plainAccessResourceMap.put(plainAccessResource.getAccessKey(),plainAccessResource);
+                plainAccessResourceMap.put(plainAccessResource.getAccessKey(), plainAccessResource);
             }
         }
 
@@ -133,7 +133,9 @@ public class PlainPermissionManager {
 
         Map<String, Object> aclAccessConfigMap = AclUtils.getYamlDataObject(fileHome + File.separator + fileName,
             Map.class);
-
+        if (aclAccessConfigMap == null || aclAccessConfigMap.isEmpty()) {
+            throw new AclException(String.format("%s file not found or isEmpty", fileHome + File.separator + fileName));
+        }
         List<Map<String, Object>> accounts = (List<Map<String, Object>>) aclAccessConfigMap.get(AclConstants.CONFIG_ACCOUNTS);
         Map<String, Object> updateAccountMap = null;
         if (accounts != null) {
@@ -164,13 +166,14 @@ public class PlainPermissionManager {
         return false;
     }
 
-    private Map<String, Object> createAclAccessConfigMap(Map<String, Object> existedAccountMap, PlainAccessConfig plainAccessConfig) {
+    private Map<String, Object> createAclAccessConfigMap(Map<String, Object> existedAccoutMap,
+        PlainAccessConfig plainAccessConfig) {
 
         Map<String, Object> newAccountsMap = null;
-        if (existedAccountMap == null) {
+        if (existedAccoutMap == null) {
             newAccountsMap = new LinkedHashMap<String, Object>();
         } else {
-            newAccountsMap = existedAccountMap;
+            newAccountsMap = existedAccoutMap;
         }
 
         if (StringUtils.isEmpty(plainAccessConfig.getAccessKey()) ||
@@ -219,7 +222,9 @@ public class PlainPermissionManager {
 
         Map<String, Object> aclAccessConfigMap = AclUtils.getYamlDataObject(fileHome + File.separator + fileName,
             Map.class);
-
+        if (aclAccessConfigMap == null || aclAccessConfigMap.isEmpty()) {
+            throw new AclException(String.format("%s file not found or isEmpty", fileHome + File.separator + fileName));
+        }
         List<Map<String, Object>> accounts = (List<Map<String, Object>>) aclAccessConfigMap.get("accounts");
         if (accounts != null) {
             Iterator<Map<String, Object>> itemIterator = accounts.iterator();
@@ -251,7 +256,9 @@ public class PlainPermissionManager {
 
         Map<String, Object> aclAccessConfigMap = AclUtils.getYamlDataObject(fileHome + File.separator + fileName,
             Map.class);
-
+        if (aclAccessConfigMap == null || aclAccessConfigMap.isEmpty()) {
+            throw new AclException(String.format("%s file not found or isEmpty", fileHome + File.separator + fileName));
+        }
         List<String> globalWhiteRemoteAddrList = (List<String>) aclAccessConfigMap.get(AclConstants.CONFIG_GLOBAL_WHITE_ADDRS);
 
         if (globalWhiteRemoteAddrList != null) {
@@ -259,7 +266,7 @@ public class PlainPermissionManager {
             globalWhiteRemoteAddrList.addAll(globalWhiteAddrsList);
 
             // Update globalWhiteRemoteAddr element in memeory map firstly
-            aclAccessConfigMap.put(AclConstants.CONFIG_GLOBAL_WHITE_ADDRS,globalWhiteRemoteAddrList);
+            aclAccessConfigMap.put(AclConstants.CONFIG_GLOBAL_WHITE_ADDRS, globalWhiteRemoteAddrList);
             if (AclUtils.writeDataObject(fileHome + File.separator + fileName, updateAclConfigFileVersion(aclAccessConfigMap))) {
                 return true;
             }