CODEWITHSUNDEEP
javalistcasting
Adam Silva
Adam Silva

Reputation: 1047

Casting an object which class is the same

I'm doing a query search on a database, that returns a list. The List is filled with variables type Object. I do an query.get(0).getClass() and it returns (something).WorkbookMappingClass. But the thing is I have to Cast that object to an WorkbookMapping object. But its giving me an I/O error(maybe its because of the Exception being practically global.)

Here's the code:

WorkbookMapping wk;
List query = ses.createQuery("FROM Workbook").list();
System.out.println("Class: "+query.get(query.size()).getClass());//return ...WorkbookMapping
wk =(WorkbookMapping)query.get(query.size());

Anybody have an idea?

Upvotes: 1

Views: 78

Answers (2)

Mubin
Mubin

Reputation: 4239

WorkbookMapping wk;
List query = ses.createQuery("FROM Workbook").list();
System.out.println("Class: "+query.get(query.size()).getClass());//return    ...WorkbookMapping
Object obj = query.get(query.size() - 1)
if(obj instanceof WorkbookMapping) {
    wk =(WorkbookMapping);
}

Irrespective of that, as Charlesworth suggested, you should have either a ClassCastException or ArrayIndexOfBoudsException (as you are accessing with query.size())

Upvotes: 1

Artem Moskalev
Artem Moskalev

Reputation: 5818

The last element of the List will be the query.size()-1 as long as the Lists are 0-based like arrays. So query.get(query.size()) returns null in your example.

Upvotes: 1

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