Sequence:
CREATE SEQUENCE stock_register_serial_no_seq
  INCREMENT 1
  MINVALUE 1
  MAXVALUE 9223372036854775807
  START 1
  CACHE 1;
Table:
CREATE TABLE stock_requirement_request
(
  serial_no serial NOT NULL,
  stock_requirement_slip_no character varying(255) NOT NULL,
  CONSTRAINT stock_requirement_request_pkey PRIMARY KEY (serial_no, stock_requirement_slip_no)
);
ALTER TABLE stock_requirement_request ALTER COLUMN stock_requirement_slip_no SET DEFAULT TO_CHAR(nextval('stock_register_serial_no_seq'::regclass),'"S"fm000000');

try {
            connection = DriverManager.getConnection("jdbc:postgresql://localhost:5432/bjspring", "postgres",
                    "postgres");
            statement = connection.createStatement();
            String sql = "select max(stock_requirement_slip_no) from stock_requirement_request";
            resultSet = statement.executeQuery(sql);
            if (resultSet.next()) {
                String numb = resultSet.getString(1);
                Integer number = Integer.valueOf(numb);

    %>
<div class="row">
                    <div class="col-25" style="float: center;">
                        <label for="stock_requirement_slip_no">Requirement Slip No</label>
                    </div>
                    <div class="col-75">
        <input type="text" id="stock_requirement_slip_no"
                            name="stock_requirement_slip_no"
                            placeholder="Enter stock requirement slip no.."
                            value="<%=number + 1%>" readonly required>

                    </div>
                </div>