java.lang.ClassCastException: java.lang.Long cannot be cast to [Ljava.lang.Long; on iterating through values from the db

Question

I am trying to fetch the last data in a table using hibernate as shown in the following snippets

query.setMaxResults(1);
         List<Long[]> rows =  query.list();
         System.out.println("current row>>>>>>  " +rows.toString());

          for (Long[] row: rows) {
                System.out.println(" ------------------- ");
                long val = (Long) row[6];
                System.out.println("current file: " + val);
            }

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

this is my query

Query query = session.createQuery("select f.currentfile.id from File f order by f.id DESC");

I am having the error at this line of the code

java.lang.ClassCastException: java.lang.Long cannot be cast to [Ljava.lang.Long;
for (Long[] row: rows) {

Please what could be wrong?

According to your querry (assuming that the id of a file is a long) you'll get a List<Long> and not a List<Long[]>. Try: List<Long> rows = query.list(); — TobiSH
– TobiSH, Commented Sep 13, 2016 at 11:57
also you have set max result to 1, it will return single Long — Shantaram Tupe
– Shantaram Tupe, Commented Sep 13, 2016 at 12:02

ravthiru · Accepted Answer · 2016-09-13 11:59:50Z

3

Your Query returns List<Long> and you are assigning List<Long[]>

Long is java.lang.Long

Long[] is [Ljava.lang.Long

edited Sep 13, 2016 at 11:59

answered Sep 13, 2016 at 11:58

ravthiru

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3 Comments

ravthiru Over a year ago

List<Long> rows = query.list();

Francis Over a year ago

Type mismatch: cannot convert from element type Long to Long[] Change type row to Long

ravthiru Over a year ago

you also need to change row to Long in for loop

Shantaram Tupe · Accepted Answer · 2016-09-13 12:07:29Z

1

remove query.setMaxResults(1);

otherwise u will get single result

try this

Edited

     List<Long> rows =  query.list();
     System.out.println("current row>>>>>>  " +rows.toString());

      for (Long val: rows) {
            System.out.println(" ------------------- ");
            System.out.println("current file: " + val);
      }

edited Sep 13, 2016 at 12:07

answered Sep 13, 2016 at 12:04

Shantaram Tupe

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1 Comment

Francis Over a year ago

Type mismatch: cannot convert from element type Long to Long[] Change type row to Long

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