public int size(){
  int a;
  for (a=arrays.length() - 1; a >= 0; a--) {
    AtomicLongArray array=arrays.get(a);
    if (array != null)     break;
  }
  return ((1 << a + 1) - 1) * BITS_PER_WORD;
}

public int size ( ) { int a ; for ( a = arrays . length ( ) - 1 ; a >= 0 ; a -- ) { AtomicLongArray array = arrays . get ( a ) ; if ( array != null ) break ; } return ( ( 1 << a + 1 ) - 1 ) * BITS_PER_WORD ; }
returns the number of bits of space actually in use
