cannot get attribute from List<Object> - Servlet

Question

In Class1 we have a method doGet and a method that returns a List with objects whom type is Animal.

public List<Animal> getAnimals() 

so I call method like:

List<Animal> animal = getAnimals();
request.setAttribute("animal_list", animal);

In Class 2 i have a method doGet too, and i want to take animal_list. My code is :

List<Animal> list500=request.getAttribute("animal_list");

but when I compile I get the message

"Object cannot be converted to List<Animal>"

Answer 1

a cast from Object to List<Animal> is necessary here:

 @SuppressWarnings("unchecked")
 List<Animal> list500= (ArrayList<Animal>)request.getAttribute("animal_list");

request.getAttribute returns just Object so you have to define the exact type via cast . Object could be everything...

as a side node: you will get a

"Unchecked cast from Object to ArrayList"

warning from the compiler . In this case you can add

"suppress the warning"

annotation . After that the warning will disappear.