public int maxId(){
  int t=-1;
  while (true) {
    int s=bits.nextSetBit(t + 1);
    if (s == -1)     return t;
 else     t=s;
  }
}

public int maxId ( ) { int t = - 1 ; while ( true ) { int s = bits . nextSetBit ( t + 1 ) ; if ( s == - 1 ) return t ; else t = s ; } }
gets the maximal defined taxon id
