code: @Override
      @FFDCIgnore(EntryNotFoundException.class)
      public List<String> getUniqueGroupIdsForUser(String uniqueUserId) throws EntryNotFoundException, RegistryException {
          int attempts = 0;
          int exceptions = 0;
          List<String> ret = new ArrayList<String>();
          for (UserRegistry registry : delegates) {
              attempts++;
              try {
                  List<String> result = registry.getUniqueGroupIdsForUser(uniqueUserId);
                  ret.addAll(result);
              } catch (EntryNotFoundException enf) {
                  exceptions++;
                  // We ignore this and keep trying. If we can't find we'll throw below
                  if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
                      Tr.debug(tc, "EntryNotFoundException caught on getUniqueGroupIdsForUser", registry, uniqueUserId, enf);
                  }
              }
          }
          if (attempts == exceptions) {
              throw new EntryNotFoundException(uniqueUserId + " does not exist");
          } else {
              return ret;
          }
      }
docs: {@inheritDoc}