private final void print( Object[] kvs ) {
    for( int i=0; i<len(kvs); i++ ) {
      Object K = key(kvs,i);
      if( K != null ) {
        String KS = (K == TOMBSTONE) ? "XXX" : K.toString();
        Object V = val(kvs,i);
        Object U = Prime.unbox(V);
        String p = (V==U) ? "" : "prime_";
        String US = (U == TOMBSTONE) ? "tombstone" : U.toString();
        System.out.println(""+i+" ("+KS+","+p+US+")");
      }
    }
    Object[] newkvs = chm(kvs)._newkvs; // New table, if any
    if( newkvs != null ) {
      System.out.println("----");
      print(newkvs);
    }
  }