code: private void setMaxBondOrder(IBond bond, IAtomContainer atomContainer) throws CDKException {
          if (bondOrderCanBeIncreased(bond, atomContainer)) {
              if (bond.getOrder() != IBond.Order.QUADRUPLE)
                  bond.setOrder(BondManipulator.increaseBondOrder(bond.getOrder()));
              else
                  throw new CDKException("Can't increase a quadruple bond!");
          }
      }
docs: This method decides the highest bond order that the bond can have and set
  it to that.
  
  @param bond The bond to be investigated
  @param atomContainer The {@link IAtomContainer} that contains the bond
  @throws CDKEXception when the bond cannot be further increased