code: public Pair<AccessControlList, DefaultAccessControlList> generateChildDirACL(Short umask) {
      AccessControlList acl = generateChildFileACL(umask);
      DefaultAccessControlList dAcl = new DefaultAccessControlList(acl);
      dAcl.setEmpty(false);
      dAcl.mOwningUser = mOwningUser;
      dAcl.mOwningGroup = mOwningGroup;
      dAcl.mMode = mMode;
      if (mExtendedEntries == null) {
        dAcl.mExtendedEntries = null;
      } else {
        dAcl.mExtendedEntries = new ExtendedACLEntries(mExtendedEntries);
      }
      return new Pair<>(acl, dAcl);
    }
docs: Creates a child directory's access ACL and default ACL based on the default ACL.
  @param umask child's umask
  @return child directory's access ACL and default ACL