Prepared statement not working when replaced with Statement?

Below is my code where i am using JDBC and to make the query run faster am replacing Statement with PrepareStatement but the page is not woking.what is the wrong i am doing??

code:

<select name="city"  onchange="Consituteshow(this.value)" required="required">  
    <option value="">Select State</option>  
    <%
        PreparedStatement stmt=null;
        DBconnection db=new DBconnection();
        Connection con=db.dbConn();
        try{
            stmt = (PreparedStatement)con.createStatement();
            ResultSet rs = stmt.executeQuery("select distinct StateID,State from election_history;");
            while(rs.next())
            {
    %>
    <option value="<%=rs.getString(2)%>"><%=rs.getString(2)%></option>  
    <%       
            } 
        }
        catch(SQLException e){
            e.printStackTrace();
        }
        finally{
            con.close();
            stmt.close();
        }
    %>
</select>

my jars are:

antlr.jar
java-image-scaling
mysql-connecotr-java 2.0.14

Error:

java.lang.NullPointerException
    at org.apache.jsp.election_005fresults_jsp._jspService(election_005fresults_jsp.java:267)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
    at java.lang.Thread.run(Unknown Source)

the following error is displayed inside console .can anyone tell what is the error??