Passing variable to method as to add to generic arraylist - Java

Question

I am wanting to take user data in one method and pass that data to an "add" method, as to add said data to a generic arraylist. However I receive the following error message...

add (T) in List cannot be applied to (java.lang.String)

I'm not sure if this is a static problem or not...

My simplified code:

List<T> list = new ArrayList<T>();

void dataCollection() {
    Scanner scan = new Scanner(System.in);
    System.out.println("type data");
    add(scan.next());
}

void add(T t) {
    list.add(t);
}

Eran · Accepted Answer · 2017-11-15 09:38:00Z

1

If you want to add Strings to your List, define it as a List<String>, not List<T>.

A List<T> might be (depending on how your class is instantiated), for example, a List<Integer>, which can't hold Strings.

If you truly need your List to be generic, you shouldn't be adding Strings to it.

answered Nov 15, 2017 at 9:38

Eran

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1 Comment

physicsboy Over a year ago

Thanks for the advice Eran. This is a first adventure into generics for me, so I'm still learning!

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