code: @Override
      public void afterPropertiesSet() throws Exception {
          final Map<String, Set<String>> resultAttributeMapping = this.getResultAttributeMapping();
          if (this.setReturningAttributes && resultAttributeMapping != null) {
              this.searchControls.setReturningAttributes(resultAttributeMapping.keySet().toArray(new String[resultAttributeMapping.size()]));
          }
  
          if (this.contextSource == null) {
              throw new BeanCreationException("contextSource must be set");
          }
      }
docs: /* (non-Javadoc)
  @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()