ansaurus

Question

java.lang.ClassCastException: java.lang.String cannot be cast to [Ljava.lang.Object

Answer 1

+3 A:

You can just write:

vgDetails = new Route();                                 
vgDetails.setRouteName ((String)companyList.get(i));

companyList is already a list of strings because you select just one column.

Additionally, as Thilo's answer also suggests, you can cast your result directly to a List<string> instead of using List<?>.

Ronald Wildenberg 2010-09-23 10:23:06

Answer 2

A:

Your companyList contains Strings, not Object[].

You should write

List<String> companyList = (List<String>) session.createSQLQuery (
      "select name from company where company_id=?", companyId).list();


for (String routeName: companyList) {
        vgDetails = new Route();                            
        vgDetails.setRouteName (routeName);                     
        routeList.add(vgDetails);       
    }

Thilo 2010-09-23 10:23:54

That won't solve the problem because it still leaves the cast to `Object[]` that causes the exception.

Ronald Wildenberg 2010-09-23 10:26:13

There will be no more cast to Object[]. That would be a compile error now.

Thilo 2010-09-23 10:27:26

That's weird. I saw a first version of your answer where only the `List<String>` cast was described, not the new for loop implementation without the cast to `Object[]`... But I don't see that you've edited your answer...

Ronald Wildenberg 2010-09-23 10:36:20

@Ronald. That was a very fast edit. But even with only the first line, the cast to Object[] would become impossible, thanks to generics it would have to be removed in order to compile.

Thilo 2010-09-23 10:41:34

@Thilo - You're right. Instead of a runtime error it would now have become a compile-time error.

Ronald Wildenberg 2010-09-23 11:32:48

Answer 3

A:

Hibernate is return an array of String (aka a List of type String)

 List<?> companyList = session.createSQLQuery ("select name " +
                                                  "from company "+
                                                  "where company_id= " + companyId).list();

Because your query returns a String of names from Company table.

What you have to do return a List

 List<String> companyList = (List<String>)session.createSQLQuery ("select name " +
                                                  "from company "+
                                                  "where company_id= " + companyId).list();

Change your error, from this:

 vgDetails = new Route(); 
            Object[] row = (Object[])companyList.get(i);                                 
            vgDetails.setRouteName ((String)row[0]);                     
            routeList.add(vgDetails);

To this:

vgDetails = new Route();                                
vgDetails.setRouteName (companyList.get(i));                     
routeList.add(vgDetails);

as companyList.get(i) returns a String.

The Elite Gentleman 2010-09-23 10:32:35

ansaurus

tags:

views:

answers:

java.lang.ClassCastException: java.lang.String cannot be cast to [Ljava.lang.Object

related questions