code: @Override
      public void addProduct(IAtomContainer product, Double coefficient) {
          products.addAtomContainer(product, coefficient);
          /*
           * notifyChanged() is called by addReactant(Molecule reactant, double
           * coefficient)
           */
      }
docs: Adds a product to this reaction.
  
  @param product     Molecule added as product to this reaction
  @param coefficient Stoichiometry coefficient for this molecule
  @see   #getProducts