getting java.sql.SQLException: Closed Connection when accessing large resultset

Hello i have big data in my oracle 10g database and have to perform some calculations on every row of resultset. So i call a separate calculation class after fetching value of single row in the while(rs.next) loop. But this actually gives me multiple java.sql.SQLException: Closed Connection errors. Its like every time loop iterates this message is shown on console. So i get different result values every time on my JSP.

ORA-12519, TNS:no appropriate service handler found
The Connection descriptor used by the client was:
localhost:1521:dir

    at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
    at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:261)
    at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:387)
    at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:414)
    at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:165)
    at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:35)
    at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:801)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at asset.management.arms.loginmodule.ConnectionManager.getConnection(ConnectionManager.java:23)
    at asset.management.arms.utilitiesreport.pipe_calculations.pipe_parameters_costing(pipe_calculations.java:49)
    at asset.management.arms.utilitiesreport.Afline.afline_renwcost(Afline.java:55)
    at asset.management.arms.utilitiesreport.UtilitiesDAO.utility(UtilitiesDAO.java:17)
    at asset.management.arms.utilitiesreport.Utilitiesreportrequest.doPost(Utilitiesreportrequest.java:24)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:879)
    at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
    at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
    at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
    at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
    at java.lang.Thread.run(Unknown Source)
 java.sql.SQLException: Closed Connection

My java code is here:-

package asset.management.arms.utilitiesreport;

import java.math.BigDecimal;
import java.sql.*;
import java.util.ArrayList;

    import asset.management.arms.loginmodule.ConnectionManager;

    public class Afline {

        Connection currentCon = null;

        ResultSet rs = null;
        Statement stmt = null;


        public long afline_renwcost(){

            long sum = 0;
            ArrayList<Long> list = new ArrayList<Long>();

            String sq="select pipe_dia, geom_length,pipe_matrl,status from sp_afline where status = 'ACTIVE'";




            try{
            currentCon = ConnectionManager.getConnection();
            stmt=currentCon.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                    ResultSet.CONCUR_UPDATABLE);
            rs = stmt.executeQuery(sq);


            while(rs.next()){

                String pipe_dia = rs.getString("pipe_dia");

                double geom_length = rs.getDouble("geom_length");
                //BigDecimal geom_l = rs.getBigDecimal("geom_length");
                //String geom_l = rs.getString("geom_length");
                //Long geom_length = Long.parseLong(rs.getString("geom_length"));
                String pipe_matrl = rs.getString("pipe_matrl");

                if(pipe_dia.equalsIgnoreCase("null")){
                    pipe_dia = "0";

                }

                //long geom_length = Long.parseLong(geom_l.trim());

                 //int pipe_diameter = Integer.parseInt(pipe_dia);

                pipe_calculations pipe = new pipe_calculations(pipe_dia, geom_length,pipe_matrl);

                list.add(pipe.pipe_parameters_costing());


            }   


            }catch (Exception ex) 
            {
             System.out.println(" " + ex);
            }
             finally 
                {
                if (rs != null) {
                      try {
                         rs.close();
                      } catch (Exception e) {}
                         rs = null;
                      }

                   if (stmt != null) {
                      try {
                         stmt.close();
                      } catch (Exception e) {}
                         stmt = null;
                      }

                   if (currentCon != null) {
                      try {
                         currentCon.close();
                      } catch (Exception e) {
                      }

                      currentCon = null;
                   }
                }

             for(int i=0; i < list.size(); i++){
                    sum = sum + list.get(i);
                }



            return sum;
        }



    }

other class which perform calculations:-

package asset.management.arms.utilitiesreport;

import java.sql.*;

import asset.management.arms.loginmodule.ConnectionManager;

public class pipe_calculations {

    public String pipe_dia = null;
    public double geom_length = 0;
    public String pipe_matrl = null;


    public pipe_calculations(String pipe_dia, double geom_length, String pipe_matrl){
         this.pipe_dia = pipe_dia;
         this.geom_length = geom_length;
         this.pipe_matrl = pipe_matrl;

    }

    Connection currentCon = null;
    ResultSet rs = null;
    Statement stmt = null;

    public int trench_depth;
    public double asphalt_depth;
    public int drain_rock_depth;
    public int excavation_cost;
    public int dewatering_cost;
    public int drain_rock_cost;
    public int backfill_cost;
    public int asphalt_cost;
    public double shoring_cost;
    public int dumping_cost;
    public开发者_运维知识库 int fabric_cost;
    public double labor_cost;
    public double steel_material_cost;
    public double pvc_material_cost;
    public double other_material_cost;
    public double pipe_material_cost;

    public long pipe_parameters_costing(){

        long total_pipe_cost = 0;

        String sq= "Select * from pipe_parameters_and_pricing";

        try{
        currentCon = ConnectionManager.getConnection();
        stmt=currentCon.createStatement();
        rs = stmt.executeQuery(sq);


        while(rs.next()){

            trench_depth = rs.getInt("TRENCH_DEPTH");
            asphalt_depth = rs.getDouble("ASPHALT_DEPTH");
            drain_rock_depth = rs.getInt("DRAIN_ROCK_DEPTH");
            excavation_cost = rs.getInt("EXCAVATION_COST");
            dewatering_cost = rs.getInt("DEWATERING_COST");
            drain_rock_cost = rs.getInt("DRAIN_ROCK_COST");
            backfill_cost = rs.getInt("BACKFILL_COST");
            asphalt_cost = rs.getInt("ASPHALT_COST");
            shoring_cost = rs.getDouble("SHORING_COST");
            dumping_cost = rs.getInt("DUMPING_COST");
            fabric_cost = rs.getInt("FABRIC_COST");
            labor_cost = rs.getDouble("LABOR_COST");
            steel_material_cost = rs.getDouble("STEEL_MATERIAL_COST");
            pvc_material_cost = rs.getDouble("PVC_MATERIAL_COST");
            other_material_cost = rs.getDouble("OTHER_MATERIAL_COST");



            int trench_width = trench_width_fx(pipe_dia);

            int backfill_depth = backfill_depth_fx(trench_depth,asphalt_depth,drain_rock_depth);

            long trench_volume = trench_volume_fx(trench_width, trench_depth, geom_length);

            long excavation_cost_pricing = excavation_cost_fx(excavation_cost, trench_volume);

            long dewatering_pricing = dewatering_cost_fx(dewatering_cost,geom_length);

            long drain_rock_pricing = drain_rock_cost_fx(drain_rock_cost, drain_rock_depth, trench_width,geom_length);

            long backfill_pricing = backfill_cost_fx(backfill_cost, backfill_depth, trench_width, geom_length);

            long asphalt_installed_pricing = asphalt_cost_fx(asphalt_cost, asphalt_depth, trench_width, geom_length );

            long shoring_pricing = shoring_cost_fx(shoring_cost, geom_length, trench_depth);

            long dumping_pricing = dumping_cost_fx(dumping_cost, trench_volume);

            long fabric_pricing = fabric_cost_fx(fabric_cost, geom_length);

            long dig_cost = excavation_cost_pricing + dewatering_pricing + drain_rock_pricing + backfill_pricing + asphalt_installed_pricing 
                            + shoring_pricing + dumping_pricing + fabric_pricing;

            long labor_costing = labor_cost_fx(labor_cost,geom_length);

            long material_cost = material_cost_fx(pipe_matrl,geom_length,steel_material_cost,pvc_material_cost,other_material_cost);

             total_pipe_cost = (dig_cost + labor_costing + material_cost)/30;



        }   


        }catch (Exception ex) 
        {
         System.out.println(" " + ex);
        }
         finally 
            {
            if (rs != null) {
                  try {
                     rs.close();
                  } catch (Exception e) {}
                     rs = null;
                  }

               if (stmt != null) {
                  try {
                     stmt.close();
                  } catch (Exception e) {}
                     stmt = null;
                  }

               if (currentCon != null) {
                  try {
                     currentCon.close();
                  } catch (Exception e) {
                  }

                 currentCon = null;
               }
            }

         return total_pipe_cost;
    }


    public int trench_width_fx(String pipe_dia){

        int pipe_diameter = Integer.parseInt(pipe_dia);

        int trench_width1 = pipe_diameter + 24;

        return trench_width1;
    }

    public int backfill_depth_fx(int trench_depth, double asphalt_depth, int drain_rock_depth){

        int backfill_depth1 = (int) (trench_depth - (asphalt_depth + drain_rock_depth));

        return backfill_depth1;
    }


    public long trench_volume_fx(int trench_width, int trench_depth, double geom_length){

        long trench_vol = (long) (trench_width * trench_depth * geom_length);
        return trench_vol;
    }


    public long excavation_cost_fx(int excavation_cost, long trench_volume){
        long excavation_cst = excavation_cost * (trench_volume / 27);

        return excavation_cst;

    }

    public long dewatering_cost_fx(int dewatering_cost, double geom_length){

        long dewatering = (long) (dewatering_cost * geom_length);
        return dewatering;
    }


    public long drain_rock_cost_fx(int drain_rock_cost, int drain_rock_depth, int trench_width,double geom_length){

        long cost = (long) (drain_rock_cost * (drain_rock_depth * trench_width * geom_length * (1.5525/27)));

        return cost;
    }

   public long backfill_cost_fx(int backfill_cost, int backfill_depth, int trench_width, double geom_length){


       long cost = (long) (backfill_cost * (backfill_depth * trench_width * geom_length * (1.5525/27)));

       return cost;
   }

   public long asphalt_cost_fx(int asphalt_cost, double asphalt_depth, int trench_width, double geom_length ){

       long cost = (long)(asphalt_cost * (asphalt_depth * trench_width * geom_length * (2025/27)));
       return cost;
   }

   public long shoring_cost_fx(double shoring_cost, double geom_length, int trench_depth){

      long cost = (long) (shoring_cost * (geom_length * trench_depth * 2));
      return cost;
   }

   public long dumping_cost_fx(int dumping_cost, long trench_volume){

       long cost = dumping_cost * (trench_volume / 27);
       return cost;
   }

   public long fabric_cost_fx(int fabric_cost, double geom_length){
       long cost = (long) (fabric_cost * geom_length);
       return cost;

   }

   public long labor_cost_fx(double labor_cost, double geom_length){

       long cost = (long) (labor_cost * geom_length);
       return cost;
   }

   public long material_cost_fx(String pipe_matrl,double geom_length,double steel_material_cost, double pvc_material_cost, double other_material_cost){
       long cost = 0;

       if(pipe_matrl.equalsIgnoreCase("stl")){

        cost = (long) (steel_material_cost * geom_length);   

       }
       else if (pipe_matrl.equalsIgnoreCase("pvc")){
           cost = (long) (pvc_material_cost * geom_length);
       }
       else{
           cost = (long) (other_material_cost * geom_length);
       }

       return cost; 
   }

}

Connection manager class :--

package asset.management.arms.loginmodule;

   import java.sql.*;


   public class ConnectionManager {

      static Connection con;
      static String url;

      public static Connection getConnection()
      {

         try
         {
            String url = "jdbc:oracle:thin:@localhost:1521:dir"; 
            // assuming "DataSource" is your DataSource name

            Class.forName("oracle.jdbc.driver.OracleDriver");

            try
            {               
               con = DriverManager.getConnection(url,"hr","hr"); 

            }

            catch (SQLException ex)
            {
               ex.printStackTrace();
            }
         }

         catch(ClassNotFoundException e)
         {
            System.out.println(e);
         }

      return con;
}
   }

How can i handle large set of data? Please guide me with some solution.Thanks

Looks to me that you try to open more concurrent DB connections than your DB setup allows. Try to figure out how many unclosed concurrent connection your Java code opens and what is the max connections settings of your DB.