Servlet performance speed

Question

Any advice on how to improve the performance and speed
of this servlet or any other comments please
public class LogInServlet extends HttpServlet {
    byte[] header;
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        // variables
        ServletOutputStream out;
        Calendar c;
        String day;
        String date;
        String timenow;
        Connection con = null;
        Statement stmt = null;
        ResultSet result = null;
        // setup output
        response.setContentType("text/html");
        out = response.getOutputStream();
        // get inputs
        String pass = (String)request.getParameter("*");
        String namenum = (String)request.getParameter("*")+
        ", "+
        (String)request.getParameter("*")+
        " ("+
        (String)request.getParameter("*")+
        // get current time
        c = Calendar.getInstance();
        try{
            // get db connection
            Context initCtx = new InitialContext();
            Context envCtx = (Context) initCtx.lookup("java:comp/env");
            DataSource ds = (DataSource)envCtx.lookup("jdbc/*");
            con = ds.getConnection();
            stmt = con.createStatement();
            result = stmt.executeQuery("*");
            // check username
            if(result.next()){
                // check password
                if(result.getString("*").equals(pass)){
                    // SOLVES LOWERCASE PROBLEM
                    namenum = result.getString("*");
                    day = getDay(c);
                    date = getDate(c);
                    stmt.close();
                    stmt = null;
                    stmt = con.createStatement();
                    result.close();
                    result = null;
                    result = stmt.executeQuery("*");
                    // check if setup to login
                    if(result.next()){
                        // check if logged in already
                        if(!date.equals(result.getString("*"))){
                            stmt.close();
                            stmt = null;
                            stmt = con.createStatement();
                            result.close();
                            result = null;
                            result = stmt.executeQuery("*");
                            result.next();
                            String time = result.getString(day+"_start");
                            timenow = getTime(c);
                            // check if late
                            if(checkIfLate(c,time)){
                                stmt.close();
                                stmt = null;
                                stmt = con.createStatement();
                                result.close();
                                result = null;
                                result = stmt.executeQuery("*");
                                // check if timeoff booked
                                if(!result.next()){
                                    // add late record
                                    stmt.close();
                                    stmt = null;
                                    stmt = con.createStatement();
                                    stmt.executeUpdate("*");
                                    // update login
                                    stmt.close();
                                    stmt = null;
                                    stmt = con.createStatement();
                                    stmt.executeUpdate("*");
                                    // complience
                                    stmt.close();
                                    stmt = null;
                                    stmt = con.createStatement();
                                    stmt.executeUpdate("*");
                                    // late
                                    out.write(header);
                                    out.print("</body></html>");
                                    out.close();
                                else{
                                    // update login
                                    stmt.close();
                                    stmt = null;
                                    stmt = con.createStatement();
                                    stmt.executeUpdate("*");
                                    // complience
                                    stmt.close();
                                    stmt = null;
                                    stmt = con.createStatement();
                                    stmt.executeUpdate("*");
                                    // ok
                                    out.write(header);
                                    out.println("</body></html>");
                                    out.close();
                            else{
                                // update loging
                                stmt.close();
                                stmt = null;
                                stmt = con.createStatement();
                                stmt.executeUpdate("*");
                                // complience
                                stmt.close();
                                stmt = null;
                                stmt = con.createStatement();
                                stmt.executeUpdate("*");
                                // ok
                                out.write(header);
                                out.println("</body></html>");
                                out.close();
                        else{
                            out.write(header);
                            // alreadyLoggedIn
                            out.println("</body></html>");
                            out.close();
                    else{
                        out.write(header);
                        // notSetupLogin
                        out.println("</body></html>");
                        out.close();
                else{
                    out.write(header);
                    // passwordIncorrect
                    out.println("</body></html>");
                    out.close();
            else{
                out.write(header);
                // nameIncorrect
                out.println("</body></html>");
                out.close();
        catch(Exception e){
            out.write(header);
            out.println("</body></html>");
            out.close();
        finally{
            if(result != null){
                try{
                    result.close();
                catch(SQLException e){
                result = null;
            if(stmt != null){
                try{
                    stmt.close();
                catch(SQLException e){
                stmt = null;
            if(con != null){
                try{
                    con.close();
                catch(SQLException e){
                con = null;
    private boolean checkIfLate(Calendar c,String t){
        StringTokenizer stz = new StringTokenizer(t,":");
        int sh = Integer.parseInt(stz.nextToken());
        int sm = Integer.parseInt(stz.nextToken());
        int ch = c.get(Calendar.HOUR_OF_DAY);
        int cm = c.get(Calendar.MINUTE);
        if(ch > sh)
            return true;
        else if(ch == sh){
            if(cm > sm)
                return true;
            else
                return false;
        else
            return false;
    private String getTime(Calendar c){
        int t = c.get(Calendar.MINUTE);
        if(t < 10)
            return c.get(Calendar.HOUR_OF_DAY)+":0"+t;
        else
            return c.get(Calendar.HOUR_OF_DAY)+":"+t;
    private String getFullDay(String d){
        if("mon".equals(d))
            return "Monday";
        else if("tue".equals(d))
            return "Tuesday";
        else if("wed".equals(d))
            return "Wednesday";
        else if("thu".equals(d))
            return "Thursday";
        else if("fri".equals(d))
            return "Friday";
        else
            return "Sunday";
    private String getDay(Calendar c){
        int d1 = c.get(Calendar.DAY_OF_WEEK);
        if(d1 == 2)
            return "mon";
        else if(d1 == 3)
            return "tue";
        else if(d1 == 4)
            return "wed";
        else if(d1 == 5)
            return "thu";
        else if(d1 == 6)
            return "fri";
        else
            return "z";
    private String getDate(Calendar c){
        int dateI1 = c.get(Calendar.MONTH)+1;
        int dateI2 = c.get(Calendar.DAY_OF_MONTH);
        if(dateI1 < 10){
            if(dateI2 < 10)
                return Integer.toString(c.get(Calendar.YEAR))+
                "-"+
                "0"+
                Integer.toString(dateI1)+
                "-"+
                "0"+
                Integer.toString(dateI2);
            else
                return Integer.toString(c.get(Calendar.YEAR))+
                "-"+
                "0"+
                Integer.toString(dateI1)+
                "-"+
                Integer.toString(dateI2);
        else{
            if(dateI2 < 10)
                return Integer.toString(c.get(Calendar.YEAR))+
                "-"+
                Integer.toString(dateI1)+
                "-"+
                "0"+
                Integer.toString(dateI2);
            else
                return Integer.toString(c.get(Calendar.YEAR))+
                "-"+
                Integer.toString(dateI1)+
                "-"+
                Integer.toString(dateI2);
    protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException,IOException {
        processRequest(request, response);
    protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException,IOException {
        processRequest(request, response);
    public String getServletInfo() {
        return "Short description";
    public void destroy() {
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
        header = "<HTML><HEAD><TITLE>*".getBytes();
}

Answer 1

DrClap / AnyOne
The problem I'm having is that everybody uses this servlet at around the
same time and this causes the memory usage and cycles to spike and
halts other application running on the server.
I was hoping that by speeding up the application,so that people could get
in and out of the servlet quickly this would reduce the memory usage
as some people would finish before the next people use it.
I also wanted to decrease the amount of memory the servlet uses.
The garbage collection and tomcat are tuned.
I want to optimise the code so that I can restrict the JVM to use the
least amount of memory.
I'm assured the query strings and index's are optimised.
The code snippet above yielded a 30% increase in execution time
(this was using a loadtester and thousands of requests on just that piece of code)
I'm going to give preparedstatements a try to see if it changes speed
(the data is cleaned using javascript on the clientside)
Questions / Comments
Connection Pooling:
Not if you used a connection pool, which you should be doing anyway. And if you're putting all your code >>in one giant class just to avoid creating an object, you're doing the wrong thing.That is exactly why I put the code in the one servlet.
If I set the max connections number to the maximum number of users
and by putting all the code in one servlet each user will use only one connection:
1. therefore there will be no one waiting for a connection to become available (increases speed)
2. the less connections created the less memory used
Is this thinking correct?????
Servlet HTML vs JSP
I know it is correct design to keep the view away from business logic
but
1. Is it quicker and less memory hungry to use ServletOutputStream to print html
or requestDispatcher to jsp?????
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