How to have the Java method return a generic list of any type?

Question

I would like to write a method that would return a list of any type without the need to typecast anything.

List<User> users = magicalListGetter(User.class);

List<Vehicle> vehicles = magicalListGetter(Vehicle.class);

List<String> strings = magicalListGetter(String.class);

What would the method signature look like?

Answer 1

private Object actuallyT;

public <T> List<T> magicalListGetter(Class<T> klazz) {

    List<T> list = new ArrayList<>();

    list.add(klazz.cast(actuallyT));

    try {

        list.add(klazz.getConstructor().newInstance()); // If default constructor

    } ...

    return list;

}

You can give a generic type parameter to a method too. You would need the correct class instance to create things(klazz.getConstructor().newInstance()).

Want to learn Java? Check put the core Java certification from Intellipaat.