Getting java.lang.NullpointerException while closing resultset aft using it

Question

Hi,
I kindly request to share your ideas reg. my problem.
I am opening a database connection using connection pool and i am using two or more resultsets and statement objects.I am closing these objects at the end of their usage.But i am getting java.lang.NullpointerException when i close them(if i don't close them it works fine). what might be the reason. Had i did any thing wrong in the code.
please view the code
public String storeNewConnection(String CIRCLE,String DIVISION,String SUB_DIVISION,String SECTION,String CONSUMER_NAME,String FATHER_NAME,String STREET_NAME,String DOOR_NO,String TOWN_CITY,String LAND_MARK,String PINCODE,String STDCODE,String PHONE_NO,String EMAIL,String NEIGHBOUR_SCNO,String DOCUMENT_CODE,String LT_APR_NO,String year1,String month1,String day1,String PCBNO,String CONSUMER_STATUS,String SOCIAL_GROUP,String CATEGORY_SUPPLY,String LOCATION_PREMISES,String PURPOSE_OF_SUPPLY,String DURATION,String LOAD_TYPE,String CONNECTED_LOAD,String CONTRACTED_LOAD,String APPLICATION_FEE,String DEVELOPMENT_CHARGES,String SECURITY_DEPOSIT,String ADDL_SECURITY_DESPOSIT,String DEPOSITED_THRU,String DD_CHEQUE_DETAILS,String year2,String month2,String day2,String REMARKS,String POLE_NO)
          int count=0;
          Statement st=null;
          ResultSet rs=null,rs1=null,rs2=null,rs3=null;
          PreparedStatement pst=null;
          String result="",query="",sysDate="",sysDate2="";
          String reg_no = "";
          try
               st=con.createStatement();
               //Check dates with sys date
               String date1 =null;                    
               String date2 =null;
               if(! (year1.equals("") || month1.equals("") || day1.equals("")) )
                    date1=day1+"-"+month1+"-"+year1;
                    rs2=st.executeQuery("select round(to_date('"+date1+"','dd-Mon-yyyy')-to_date(sysdate,'dd-Mon-yy')) from dual");
                    rs2.next();
                    if(rs2.getInt(1) != 0)
                         return "false";                              
               if(! (year2.equals("") || month2.equals("") || day2.equals("")) )
                    date2=day2+"-"+month2+"-"+year2;
                    rs3=st.executeQuery("select round(to_date('"+date2+"','dd-Mon-yyyy')-to_date(sysdate,'dd-Mon-yy')) from dual");
                    rs3.next();
                    if(rs3.getInt(1) != 0)
                         return "false";     
               rs1=st.executeQuery("select to_char(sysdate,'yyyyMONdd'),to_char(sysdate,'dd-Mon-yyyy') from dual");
               rs1.next();
               sysDate=rs1.getString(1);
               sysDate2=rs1.getString(2);
               rs=st.executeQuery("select max(SERIAL_NO) from NEW_CONNECTIONS where to_char(sysdate,'yyyy') = to_char(REG_DATE,'yyyy') and to_char(sysdate,'mm') = to_char(REG_DATE,'mm') and SUB_DIVISION_CODE = "+SUB_DIVISION+" and DIVISION_CODE = "+DIVISION+" and CIRCLE_CODE = "+CIRCLE+" ");
               if(rs.next())
                    count = rs.getInt(1);
                    count++;                              
               else
                    count=1;
               query="insert into NEW_CONNECTIONS ( "+
                    " REG_NO,SERIAL_NO,REG_DATE,CIRCLE_CODE,DIVISION_CODE,SUB_DIVISION_CODE,SECTION_CODE, "+
                    " CONSUMER_NAME,FATHER_NAME,STREET_NAME,DOOR_NO,TOWN_CITY,LAND_MARK,PINCODE, "+
                    " STDCODE,PHONE_NO,EMAIL,NEIGHBOUR_SCNO,DOCUMENT_CODE,LT_APR_NO,LT_APR_DATE, "+
                    " PCBNO,CONSUMER_STATUS,SOCIAL_GROUP,CATEGORY_SUPPLY,LOCATION_PREMISES,PURPOSE_OF_SUPPLY,"+
                    " DURATION,LOAD_TYPE,CONNECTED_LOAD,CONTRACTED_LOAD,APPLICATION_FEE,DEVELOPMENT_CHARGES, "+
                    " SECURITY_DEPOSIT,ADDL_SECURITY_DEPOSIT,DEPOSITED_THRU,DD_CHEQUE_DETAILS,DD_CHEQUE_DATE,REMARKS,APPLICATION_STATUS,POLE_NO) "+
                    " values(?,?,'"+sysDate2+"',?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)";
               pst = con.prepareStatement(query);
               String cnt ="";
               if(count <= 9)
                    cnt="0000";
               else if(count <= 99)
                    cnt="000";
               else if(count <= 999)
                    cnt="00";
               else if(count <= 9999)
                    cnt="0";
               cnt+=Integer.toString(count);
               reg_no = CIRCLE+DIVISION+SUB_DIVISION+SECTION+"N"+cnt+sysDate;               
               int serial_no =count;
               int pin = 0;
               if(!PINCODE.equals(""))
                    pin =Integer.parseInt(PINCODE);
               int std = 0;
               if(!STDCODE.equals(""))
                    std = Integer.parseInt(STDCODE);
               int status = Integer.parseInt(CONSUMER_STATUS);
               int social_group = Integer.parseInt(SOCIAL_GROUP);
               int supply = Integer.parseInt(CATEGORY_SUPPLY);
               int location = Integer.parseInt(LOCATION_PREMISES);
               int purpose = Integer.parseInt(PURPOSE_OF_SUPPLY);
               int duration = Integer.parseInt(DURATION);
               int laod_type = Integer.parseInt(LOAD_TYPE);
               float conn_load = Float.parseFloat(CONNECTED_LOAD);
               int cont_load = 0;
               if(!CONTRACTED_LOAD.equals(""))
                    cont_load =Integer.parseInt(CONTRACTED_LOAD);
               int app_fee = Integer.parseInt(APPLICATION_FEE);
               int dev_chg = Integer.parseInt(DEVELOPMENT_CHARGES);
               int sec_dep = Integer.parseInt(SECURITY_DEPOSIT);
               int addl_sec_dep = 0;     
               if(!ADDL_SECURITY_DESPOSIT.equals(""))
                    addl_sec_dep =Integer.parseInt(ADDL_SECURITY_DESPOSIT);
               int dep_thru = Integer.parseInt(DEPOSITED_THRU);          
               pst.setString(1,reg_no);
               pst.setInt(2,serial_no);
               pst.setString(3,CIRCLE);
               pst.setString(4,DIVISION);
               pst.setString(5,SUB_DIVISION);
               pst.setString(6,SECTION);
               pst.setString(7,CONSUMER_NAME);
               pst.setString(8,FATHER_NAME);
               pst.setString(9,STREET_NAME);
               pst.setString(10,DOOR_NO);
               pst.setString(11,TOWN_CITY);
               pst.setString(12,LAND_MARK);
               pst.setInt(13,pin);
               pst.setInt(14,std);
               pst.setString(15,PHONE_NO);
               pst.setString(16,EMAIL);
               pst.setString(17,NEIGHBOUR_SCNO);
               pst.setString(18,DOCUMENT_CODE);
               pst.setString(19,LT_APR_NO);
               pst.setString(20,date1);
               pst.setString(21,PCBNO);
               pst.setInt(22,status);
               pst.setInt(23,social_group);
               pst.setInt(24,supply );
               pst.setInt(25,location);
               pst.setInt(26,purpose);
               pst.setInt(27,duration);
               pst.setInt(28,laod_type);
               pst.setFloat(29,conn_load );
               pst.setInt(30,cont_load);
               pst.setInt(31,app_fee);
               pst.setInt(32,dev_chg);
               pst.setInt(33,sec_dep);
               pst.setInt(34,addl_sec_dep);
               pst.setInt(35,dep_thru );
               pst.setString(36,DD_CHEQUE_DETAILS);
               pst.setString(37,date2);
               pst.setString(38,REMARKS);
               pst.setInt(39,1);
               pst.setString(40,POLE_NO);
               pst.executeUpdate();
               result=reg_no;                                   
               rs.close();
               rs=null;
               rs1.close();
               rs1=null;
               rs2.close();
               rs2=null;
               rs3.close();
               rs3=null;
               st.close();
               st=null;
               pst.close();
               pst=null;
          catch(Exception e)
               e.printStackTrace();
               result="false";
               return result;
          finally
               if (rs != null)
                    try
                         rs.close();
                    catch (SQLException e)
                    rs = null;
               if (rs1 != null)
                    try
                         rs1.close();
                    catch (SQLException e)
                    rs1 = null;
               if (rs2 != null)
                    try
                         rs2.close();
                    catch (SQLException e)
                    rs2 = null;
               if (rs3 != null)
                    try
                         rs3.close();
                    catch (SQLException e)
                    rs3 = null;
               if (st != null)
                    try
                         st.close();
                    catch (SQLException e)
                    st = null;
               if (pst != null)
                    try
                         pst.close();
                    catch (SQLException e)
                    pst = null;
          return result;
Also plz help me to improve the code if necessary so that it will work fine for multiple users
thaks & regards
Prasanth.C

Answer 1

Thanks a lot.
i replaced the code below
if (rs != null)
                    try
                         rs.close();
                    catch (SQLException e)
                    rs = null;
               if (rs1 != null)
                    try
                         rs1.close();
                    catch (SQLException e)
                    rs1 = null;
               if (rs2 != null)
                    try
                         rs2.close();
                    catch (SQLException e)
                    rs2 = null;
               if (rs3 != null)
                    try
                         rs3.close();
                    catch (SQLException e)
                    rs3 = null;
               if (st != null)
                    try
                         st.close();
                    catch (SQLException e)
                    st = null;
               if (pst != null)
                    try
                         pst.close();
                    catch (SQLException e)
                    pst = null;
instead of blindly closing the resultsets and statements
now it works fine.
One more thing, is my code structurally correct, i mean the variables, try...catch blocks,results,statements,database connections and overall coding. whether it looks like professional code.
thaks & regards,
Prasanth.C