code: protected void validateNew(final CmsAliasTableRow newEntry) {
  
          CmsRpcAction<CmsAliasEditValidationReply> action = new CmsRpcAction<CmsAliasEditValidationReply>() {
  
              @Override
              public void execute() {
  
                  start(200, true);
                  CmsAliasEditValidationRequest validationRequest = new CmsAliasEditValidationRequest();
                  List<CmsAliasTableRow> rows = m_view.getLiveData();
                  validationRequest.setEditedData(rows);
                  validationRequest.setNewEntry(newEntry);
                  validationRequest.setOriginalData(m_initialData);
                  getService().validateAliases(validationRequest, this);
              }
  
              @Override
              public void onResponse(CmsAliasEditValidationReply result) {
  
                  stop(false);
                  List<CmsAliasTableRow> tableRows = result.getChangedRows();
                  CmsAliasTableRow validatedNewEntry = result.getValidatedNewEntry();
                  if (validatedNewEntry.hasErrors()) {
                      m_view.setNewAliasPathError(validatedNewEntry.getAliasError());
                      m_view.setNewAliasResourceError(validatedNewEntry.getPathError());
                  } else {
                      m_view.clearNew();
                      tableRows.add(validatedNewEntry);
                  }
                  m_view.update(tableRows);
                  updateValidationStatus();
              }
          };
          action.execute();
      }
docs: Triggers server-side validation of the alias table and of a new entry which should be added to it.<p>
  
  @param newEntry the new entry