Could not downcast using List class in Java

Question

I've been searching for an answer for this but to no avail. My question is why is it not possible to downcast with generics. I have a class called Job and extends a class called Model

Job extends Model

Now I get a collection of Jobs from a reusable code that generates a list of Models

// error: Cannot cast from List<Model> to List<Job>
List<Job> jobs = (List<Job>) jobMapper.fetchAll();

where jobMapper.fetchAll() returns a List where each model inside it is a Job object.

I assumed this would work because I can do:

EditText mUsername = (EditText) findViewById(R.id.editUserName);

which is a simple downcasting.

Answer 1

You cant do this, because Java does not allows this. Read this. You should do the trick:

 List<Job> jobs = (List<Job>) ((List<?>)jobMapper.fetchAll());