code: protected void updateSubNav(List<NavEntry> subEntries) {
  
          m_rootLayout.clearSubNav();
          if ((subEntries == null) || subEntries.isEmpty()) {
              m_rootLayout.setSubNavVisible(false);
          } else {
              m_rootLayout.setSubNavVisible(true);
              for (NavEntry entry : subEntries) {
                  addSubNavEntry(entry);
              }
          }
      }
docs: Updates the sub navigation with the given entries.<p>
  
  @param subEntries the sub navigation entries