How to cast generic List types in java?

Question

Well, I have a class Customer (no base class).

I need to cast from LinkedList to List. Is there any clean way to do this?

Just so you know, I need to cast it

Answer 1

I did this function for that, ugly but it works

public static <T> Collection<T> cast(Collection<? super T> collection, Class<T> clazz){
    return (Collection<T>)collection;
}

Answer 2

Here's my horrible solution for doing casting. I know, I know, I shouldn't be releasing something like this into the wild, but it has come in handy for casting any object to any type:

public class UnsafeCastUtil {

    private UnsafeCastUtil(){ /* not instatiable */}

    /**
    * Warning! Using this method is a sin against the gods of programming!
    */
    @SuppressWarnings("unchecked")
    public static <T> T cast(Object o){
        return (T)o;
    }

}

Usage:

Cat c = new Cat();
Dog d = UnsafeCastUtil.cast(c);

Now I'm going to pray to the gods of programming for my sins...

Answer 3

List is an interface, LinkedList is a concrete implementation of that interface. Much of the time an implicit cast will work, assign a LinkedList to a List, or pass it to a function expecting a List and it should just `work'.

An explicit cast can also be done if necessary.

//This is valid
List<Customer> myList = new LinkedList<Customer>();

//Also Valid
List<Customer> myList = (List<Customer>) new LinkedList<Customer>();