clear duplicated attribute keys before loading them from cache to avoid NPE

dao/src/main/java/org/thingsboard/server/dao/attributes/AttributeUtils.java

@@ -21,6 +21,7 @@ import org.thingsboard.server.dao.exception.IncorrectParameterException;
 import org.thingsboard.server.dao.service.Validator;
 
 public class AttributeUtils {
+
     public static void validate(EntityId id, String scope) {
         Validator.validateId(id.getId(), "Incorrect id " + id);
         Validator.validateString(scope, "Incorrect scope " + scope);

dao/src/main/java/org/thingsboard/server/dao/attributes/CachedAttributesService.java

@@ -42,6 +42,7 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -123,6 +124,7 @@ public class CachedAttributesService implements AttributesService {
                     return result;
                 } catch (Throwable e) {
                     cacheTransaction.rollback();
+                    log.debug("Could not find attribute from cache: [{}] [{}] [{}]", entityId, scope, attributeKey, e);
                     throw e;
                 }
             });
@@ -132,6 +134,7 @@ public class CachedAttributesService implements AttributesService {
     @Override
     public ListenableFuture<List<AttributeKvEntry>> find(TenantId tenantId, EntityId entityId, String scope, Collection<String> attributeKeys) {
         validate(entityId, scope);
+        attributeKeys =  new LinkedHashSet<>(attributeKeys); // deduplicate the attributes
         attributeKeys.forEach(attributeKey -> Validator.validateString(attributeKey, "Incorrect attribute key " + attributeKey));
 
         Map<String, TbCacheValueWrapper<AttributeKvEntry>> wrappedCachedAttributes = findCachedAttributes(entityId, scope, attributeKeys);
@@ -170,6 +173,7 @@ public class CachedAttributesService implements AttributesService {
                 return mergedAttributes;
             } catch (Throwable e) {
                 cacheTransaction.rollback();
+                log.debug("Could not find attributes from cache: [{}] [{}] [{}]", entityId, scope, notFoundAttributeKeys, e);
                 throw e;
             }
         });