code: public void setForceFieldConfigurator(String ffname, IChemObjectBuilder builder) throws CDKException {
          ffname = ffname.toLowerCase();
          boolean check = false;
  
          if (ffname == ffName && parameterSet != null) {
          } else {
              check = this.checkForceFieldType(ffname);
              ffName = ffname;
              if (ffName.equals("mm2")) {
                  //logger.debug("ForceFieldConfigurator: open Force Field mm2");
                  //f = new File(mm2File);
                  //readFile(f);
                  ins = this.getClass().getClassLoader()
                          .getResourceAsStream("org/openscience/cdk/modeling/forcefield/data/mm2.prm");
                  //logger.debug("ForceFieldConfigurator: open Force Field mm2 ... READY");
                  mm2 = new MM2BasedParameterSetReader();
                  mm2.setInputStream(ins);
                  //logger.debug("ForceFieldConfigurator: mm2 set input stream ... READY");
                  try {
                      this.setMM2Parameters(builder);
                  } catch (Exception ex1) {
                      throw new CDKException("Problems with set MM2Parameters due to " + ex1.toString(), ex1);
                  }
              } else if (ffName.equals("mmff94") || !check) {
                  //logger.debug("ForceFieldConfigurator: open Force Field mmff94");
                  //f = new File(mmff94File);
                  //readFile(f);
                  ins = this.getClass().getClassLoader()
                          .getResourceAsStream("org/openscience/cdk/modeling/forcefield/data/mmff94.prm");
                  mmff94 = new MMFF94BasedParameterSetReader();
  
                  mmff94.setInputStream(ins);
                  try {
                      this.setMMFF94Parameters(builder);
                  } catch (Exception ex2) {
                      throw new CDKException("Problems with set MM2Parameters due to" + ex2.toString(), ex2);
                  }
              }
          }
          //throw new CDKException("Data file for "+ffName+" force field could not be found");
      }
docs: Constructor for the ForceFieldConfigurator object
  
  @param  ffname  name of the force field data file