Correct processing requests and sending response

@@ -26,12 +26,12 @@ import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.bind.annotation.RestController;
 import org.thingsboard.rule.engine.api.MailService;
 import org.thingsboard.rule.engine.api.SmsService;
-import org.thingsboard.server.common.data.sms.config.TestSmsRequest;
 import org.thingsboard.server.common.data.AdminSettings;
 import org.thingsboard.server.common.data.UpdateMessage;
 import org.thingsboard.server.common.data.exception.ThingsboardException;
 import org.thingsboard.server.common.data.id.TenantId;
 import org.thingsboard.server.common.data.security.model.SecuritySettings;
+import org.thingsboard.server.common.data.sms.config.TestSmsRequest;
 import org.thingsboard.server.dao.settings.AdminSettingsService;
 import org.thingsboard.server.queue.util.TbCoreComponent;
 import org.thingsboard.server.service.security.permission.Operation;
@@ -67,7 +67,7 @@ public class AdminController extends BaseController {
             accessControlService.checkPermission(getCurrentUser(), Resource.ADMIN_SETTINGS, Operation.READ);
             AdminSettings adminSettings = checkNotNull(adminSettingsService.findAdminSettingsByKey(TenantId.SYS_TENANT_ID, key));
             if (adminSettings.getKey().equals("mail")) {
-                ((ObjectNode) adminSettings.getJsonValue()).put("password", "");
+                ((ObjectNode) adminSettings.getJsonValue()).remove("password");
             }
             return adminSettings;
         } catch (Exception e) {
@@ -84,7 +84,7 @@ public class AdminController extends BaseController {
             adminSettings = checkNotNull(adminSettingsService.saveAdminSettings(TenantId.SYS_TENANT_ID, adminSettings));
             if (adminSettings.getKey().equals("mail")) {
                 mailService.updateMailConfiguration();
-                ((ObjectNode) adminSettings.getJsonValue()).put("password", "");
+                ((ObjectNode) adminSettings.getJsonValue()).remove("password");
             } else if (adminSettings.getKey().equals("sms")) {
                 smsService.updateSmsConfiguration();
             }

@@ -215,6 +215,7 @@ public class DefaultSystemDataLoaderService implements SystemDataLoaderService {
         node.put("password", "");
         node.put("tlsVersion", "TLSv1.2");//NOSONAR, key used to identify password field (not password value itself)
         node.put("enableProxy", false);
+        node.put("isDemo", true);
         mailSettings.setJsonValue(node);
         adminSettingsService.saveAdminSettings(TenantId.SYS_TENANT_ID, mailSettings);
     }

@@ -52,7 +52,7 @@ public class AdminSettingsServiceImpl implements AdminSettingsService {
     public AdminSettings saveAdminSettings(TenantId tenantId, AdminSettings adminSettings) {
         log.trace("Executing saveAdminSettings [{}]", adminSettings);
         adminSettingsValidator.validate(adminSettings, data -> tenantId);
-        if (adminSettings.getKey().equals("mail") && "".equals(adminSettings.getJsonValue().get("password").asText())) {
+        if(adminSettings.getKey().equals("mail") && !adminSettings.getJsonValue().has("password")) {
             AdminSettings mailSettings = findAdminSettingsByKey(tenantId, "mail");
             if (mailSettings != null) {
                 ((ObjectNode) adminSettings.getJsonValue()).put("password", mailSettings.getJsonValue().get("password").asText());
@@ -61,7 +61,7 @@ public class AdminSettingsServiceImpl implements AdminSettingsService {
 
         return adminSettingsDao.save(tenantId, adminSettings);
     }
-    
+
     private DataValidator<AdminSettings> adminSettingsValidator =
             new DataValidator<AdminSettings>() {
 

@@ -126,10 +126,10 @@
             <input matInput formControlName="username" placeholder="{{ 'common.enter-username' | translate }}"
                    autocomplete="new-username"/>
           </mat-form-field>
-          <mat-checkbox *ngIf="!isAdd" formControlName="changePassword" style="padding-bottom: 16px;">
+          <mat-checkbox *ngIf="!isDemo" formControlName="changePassword" style="padding-bottom: 16px;">
             {{ 'admin.change-password' | translate }}
           </mat-checkbox>
-          <mat-form-field class="mat-block" *ngIf="mailSettings.get('changePassword').value || isAdd">
+          <mat-form-field class="mat-block" *ngIf="mailSettings.get('changePassword').value || isDemo">
             <mat-label translate>common.password</mat-label>
             <input matInput formControlName="password" type="password"
                    placeholder="{{ 'common.enter-password' | translate }}" autocomplete="new-password">

@@ -39,7 +39,7 @@ export class MailServerComponent extends PageComponent implements OnInit, OnDest
   mailSettings: FormGroup;
   adminSettings: AdminSettings<MailServerSettings>;
   smtpProtocols = ['smtp', 'smtps'];
-  isAdd = true;
+  isDemo = true;
 
   tlsVersions = ['TLSv1', 'TLSv1.1', 'TLSv1.2', 'TLSv1.3'];
 
@@ -61,10 +61,10 @@ export class MailServerComponent extends PageComponent implements OnInit, OnDest
         if (this.adminSettings.jsonValue && isString(this.adminSettings.jsonValue.enableTls)) {
           this.adminSettings.jsonValue.enableTls = (this.adminSettings.jsonValue.enableTls as any) === 'true';
         }
-        this.isAdd = this.adminSettings.jsonValue.isAdd;
-        delete this.adminSettings.jsonValue.isAdd;
+        this.isDemo = this.adminSettings.jsonValue.isDemo;
+        delete this.adminSettings.jsonValue.isDemo;
         this.mailSettings.reset(this.adminSettings.jsonValue);
-        this.enableMailPassword(this.isAdd);
+        this.enableMailPassword(this.isDemo);
         this.enableProxyChanged();
       }
     );

@@ -27,7 +27,7 @@ export interface AdminSettings<T> {
 export declare type SmtpProtocol = 'smtp' | 'smtps';
 
 export interface MailServerSettings {
-  isAdd: boolean;
+  isDemo: boolean;
   mailFrom: string;
   smtpProtocol: SmtpProtocol;
   smtpHost: string;