code: @Override
      public IBitFingerprint getBitFingerprint(IAtomContainer atomContainer) throws CDKException {
          generateFp(atomContainer);
          BitSet fp = new BitSet(FP_SIZE);
          for (int i = 0; i < FP_SIZE; i++) {
              if (isBitOn(i)) fp.set(i);
          }
          return new BitSetFingerprint(fp);
      }
docs: Calculate 881 bit Pubchem fingerprint for a molecule.
  
  See
  <a href="ftp://ftp.ncbi.nlm.nih.gov/pubchem/specifications/pubchem_fingerprints.txt">here</a>
  for a description of each bit position.
  
  @param atomContainer the molecule to consider
  @return the fingerprint
  @throws CDKException if there is an error during substructure
  searching or atom typing
  @see #getFingerprintAsBytes()