Update GUI.java

            @Override

            public void actionPerformed(ActionEvent e) {

                // Get the molecule path from the text field

                String moleculePath = filePathField.getText();

                outputTextArea.append("molecule path is " + moleculePath + "\n\n"); // this is here for debug, delete once finish

                // Input format for the file path is "start,end" where 'start' and 'end' are the starting and ending CID indices of molecules in PubChem

                // For example, enter 12,24 to download molecules 12-24

                String twoIndices = filePathField.getText();

                // Repurposed moleculePath should be in format "start,end"

                String[] indexes = moleculePath.split(",");

                String[] indexes = twoIndices.split(",");

                if (indexes.length == 2) {

                    String start = indexes[0];

                    String end = indexes[1];

                    moleculeDb.downloadPubChem(start, end);

                } else {

                    outputTextArea.append("indexes are " + Arrays.toString(indexes) + "\n\n"); // this is here for debug, delete once finish

                    outputTextArea.append("Invalid Input" + "\n\n");

                }

            }