Convert JPA Query getResultList to Array

Question

I have been struggling with this problem for several hours now. All I have succeeded in doing is attempt every possible way to convert a List into an array and I just get errors.
     // create native SQL query
     Query q = em.createNativeQuery("SELECT * FROM Project p");
     // get and process the results
     List<Project> list = q.getResultList();
        Project[] retVal = new Project[list.size()];
     for (int i = 0; i < list.size(); i++)
         retVal[i] = list.get(i);
     }One would assume this to work, however this generates a ClassCastException, cannot convert Object to Project, oddly because as far as I can see everything in the code is strongly typed. I think Persistence fills the typed List with Object and not Project??
So I tried:
Project[] retVal = list.toArray(new Project[0]);This generates an ArrayStoreException.
Finally I tried the basic, should generate x-lint warning:
Project[] retVal = (Project[])(list.toArray());This also return ClassCastException, same reason as the first attempt.
I want my WebService function to return a standard Project[] not the java.lang.List class. But it seems JPA queries only support getting a List. I have googled to no end for a solution. Help appreciated!
Thanks.

Answer 1

You are almost right, you can solve this two ways as below:
First, use native query with result class reference.
Second, use JPA query with createQuery method.
Both the options should work, see code below:
// First option, create native SQL query with result class reference.
Query q = em.createNativeQuery("SELECT * FROM Project p",Project.class);
// Second option, Create JPA Query.
// Query q = em.createQuery("SELECT p FROM Project p");
// get and process the results
List<Project> list = q.getResultList();
// Putting result to an array
Project[] retVal = new Project[list.size()];
list.toArray(retVal);*Cheers,
typurohit* (Tejas Purohit)