Exception in thread "main" java.util.NoSuchElementException

Question

Hello there,
I need to store resultset values in arrays.
Following is my code:
(Note : The function uses the jdbc connection with mysql that is return from other function.)
public static void getResultSetInArray(Connection con) throws Exception
Map list = new HashMap();
Statement stmt = con.createStatement(ResultSet.TYPE_FORWARD_ONLY,ResultSet.CONCUR_READ_ONLY);
ResultSet rs = stmt.executeQuery("show columns from launchcomm.events");
while(rs.next())
list.put(rs.getString("Field"),rs.getString("Type"));
rs.close();
con.close();
System.out.println("List = " + list + "\n");
Iterator iter = null;
iter = list.keySet().iterator();
System.out.println("iter = " + iter);
String field;
String type;
int i=1;
System.out.println("list size = " + list.size());
while(iter.hasNext() != false)
System.out.println("iter.hasNext() = " + iter.hasNext() +"......" +(i++));
System.out.println("iter.next() = " + iter.next());
field = (String)iter.next();
type = (String)list.get(iter.next());
Following is my output with error:
List = {folder_name=varchar(50), is_repeat=tinyint(1), footer=text, thankyou_email=text, box_header_bg_color=varchar(25), organization_id=int(11), attendee_delete_right=tinyint(1), show_ticket_remaining=tinyint(1), order_confirmation_email=text, save_for_later=tinyint(1), start_register=tinyint(4), id=int(11), logo=varchar(100), publish=tinyint(1), end_unregister=datetime, owner_id=int(11), confirmation_email=text, audience_id=int(11), event_color_code=varchar(30), showcalendar=tinyint(1), registration_enddate=datetime, directory_name=varchar(20), eventstatus_id=int(11), contact_id=int(11), password_protect=tinyint(1), include_header=tinyint(1), thankyou_page=text, header=text, is_hotel_capacity=tinyint(1), want_close=tinyint(1), travel_housing_request=tinyint(1), box_header_text_color=varchar(25), default_location_id=int(11), end_reg_modification=datetime, user_id=int(11), passkey_eventcode=varchar(255), page_size=int(11), passkey_password=varchar(255), event_capacity=int(11), box_text_color=varchar(25), updated_on=datetime, link_color=varchar(25), ends_on=datetime, hotel_capacity=int(11), template_id=int(11), allow_overlap_session=tinyint(1), starts_on=datetime, reg_another_button=varchar(50), passkey_partnerid=int(11), personalized_url=tinyint(1), hide_start_date=tinyint(1), hide_end_date=tinyint(1), include_footer=tinyint(1), text_color=varchar(25), allow_another_registrant=tinyint(1), passkey_eventid=int(11), resize=tinyint(1), default_closetemplate=tinyint(1), dateformat=text, personalize_agenda=tinyint(1), cssfile_id=int(11), passkey_information=tinyint(1), confirmation_page=text, activate_waitlist=tinyint(1), box_border_color=varchar(25), google_analytics_code=text, show_iframe_design=tinyint(1), confirmation_mail_format=tinyint(1), url=varchar(100), bg_color=varchar(25), package_id=int(11), name=varchar(200), password=varchar(50), capacity=int(11), modify_registration=tinyint(1), is_event_capacity=tinyint(1), include_css=tinyint(1), passkey_username=varchar(255), created_on=datetime, promote_url=varchar(100), page_views=int(11), box_bg_color=varchar(25), title_text_color=varchar(25), registration_open_text=text, require_login=tinyint(1), closetemplate_description=text, registration_startdate=datetime, domain=varchar(200), timezone_id=varchar(100), description=text, tag=varchar(255), allow_unregister=tinyint(1), order_confirmation_page=text, css=text, showmap=tinyint(1)}
iter = java.util.HashMap$KeyIterator@18a47e0
list size = 95
iter.hasNext() = true......1
iter.next() = folder_name
iter.hasNext() = true......2
iter.next() = footer
iter.hasNext() = true......3
iter.next() = box_header_bg_color
iter.hasNext() = true......4
iter.next() = attendee_delete_right
iter.hasNext() = true......5
iter.next() = order_confirmation_email
iter.hasNext() = true......6
iter.next() = start_register
iter.hasNext() = true......7
iter.next() = logo
iter.hasNext() = true......8
iter.next() = end_unregister
iter.hasNext() = true......9
iter.next() = confirmation_email
iter.hasNext() = true......10
iter.next() = event_color_code
iter.hasNext() = true......11
iter.next() = registration_enddate
iter.hasNext() = true......12
iter.next() = eventstatus_id
iter.hasNext() = true......13
iter.next() = password_protect
iter.hasNext() = true......14
iter.next() = thankyou_page
iter.hasNext() = true......15
iter.next() = is_hotel_capacity
iter.hasNext() = true......16
iter.next() = travel_housing_request
iter.hasNext() = true......17
iter.next() = default_location_id
iter.hasNext() = true......18
iter.next() = user_id
iter.hasNext() = true......19
iter.next() = page_size
iter.hasNext() = true......20
iter.next() = event_capacity
iter.hasNext() = true......21
iter.next() = updated_on
iter.hasNext() = true......22
iter.next() = ends_on
iter.hasNext() = true......23
iter.next() = template_id
iter.hasNext() = true......24
iter.next() = starts_on
iter.hasNext() = true......25
iter.next() = passkey_partnerid
iter.hasNext() = true......26
iter.next() = hide_start_date
iter.hasNext() = true......27
iter.next() = include_footer
iter.hasNext() = true......28
iter.next() = allow_another_registrant
iter.hasNext() = true......29
iter.next() = resize
iter.hasNext() = true......30
iter.next() = dateformat
iter.hasNext() = true......31
iter.next() = cssfile_id
iter.hasNext() = true......32
iter.next() = confirmation_page
iter.hasNext() = true......33
iter.next() = box_border_color
iter.hasNext() = true......34
iter.next() = show_iframe_design
iter.hasNext() = true......35
iter.next() = url
iter.hasNext() = true......36
iter.next() = package_id
iter.hasNext() = true......37
iter.next() = password
iter.hasNext() = true......38
iter.next() = modify_registration
iter.hasNext() = true......39
iter.next() = include_css
iter.hasNext() = true......40
iter.next() = created_on
iter.hasNext() = true......41
iter.next() = page_views
iter.hasNext() = true......42
iter.next() = title_text_color
iter.hasNext() = true......43
iter.next() = require_login
iter.hasNext() = true......44
iter.next() = registration_startdate
iter.hasNext() = true......45
iter.next() = timezone_id
iter.hasNext() = true......46
iter.next() = tag
iter.hasNext() = true......47
iter.next() = order_confirmation_page
iter.hasNext() = true......48
iter.next() = showmap
Exception in thread "main" java.util.NoSuchElementException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:844)
at java.util.HashMap$KeyIterator.next(HashMap.java:877)
at GetDataTypeFromDB.getResultSetInArray(GetDataTypeFromDB.java:57)
at GetDataTypeFromDB.main(GetDataTypeFromDB.java:16)
I am unable to fine the reason for the exception.
Please help me to solve my problem.
Regards,
Thevoice
Edited by: TheVoice on May 14, 2008 12:01 AM

Answer 1

TheVoice wrote:
while(iter.hasNext() != false)
System.out.println("iter.hasNext() = " + iter.hasNext() +"......" +(i++));
System.out.println("iter.next() = " + iter.next());
field = (String)iter.next();
type = (String)list.get(iter.next());
}Your major problem is that iter.next() advances one place every time you call it, so in every iteration of that loop, you advance three steps. The first step is guaranteed to be okay, because you checked it with iter.hasNext(), but the other two are not. In addition, you are in effect "skipping" the printing of two out of every three items.
To print out every item, you probably want to do something like this (call it only one and store it in a variable):
while(iter.hasNext())
    String field = (String)iter.next();
    System.out.println("iter.hasNext() = " + iter.hasNext() +"......" +(i++));
    System.out.println("iter.next() = " + field);
    String type = (String)list.get(field);
}For additional clarity, I would recommend using Generics, Map.entrySet(), and the for-each loop:
public static void getResultSetInArray(Connection con) throws Exception
    Map<String,String> list = new HashMap<String,String>();
    Statement stmt = con.createStatement(ResultSet.TYPE_FORWARD_ONLY,ResultSet.CONCUR_READ_ONLY);
    ResultSet rs = stmt.executeQuery("show columns from launchcomm.events");
    while(rs.next())
        list.put(rs.getString("Field"),rs.getString("Type"));
    rs.close();
    con.close();
    for (Map.Entry<String,String> e : list.entrySet())
        String field = e.getKey();
        String type = e.getValue();
        // do stuff with them
}Edited by: spoon_ on May 14, 2008 7:34 PM