Passing array to function with generic data type argument

Question

Why does this work

public E a;
public MySortedArray(E asdf){
    a = asdf;
}

and this doesn't?

public E[] a;
public MySortedArray(E[] asdf){
    a = asdf;
}

How can I achieve the second when let's say I do

    MySortedArray<Integer> test = new MySortedArray<>(integersArray);

See Restrictions on Generics in the Java Tutorial. For the second, you should use List<E> instead of E[] and use the List API instead of array subscripting. — Ted Hopp
– Ted Hopp, Commented Nov 12, 2014 at 19:38
@TedHopp I don't think that this involves the creation of a generic array as in your "duplicate of"; just the passing of an array to a generic class. — rgettman
– rgettman, Commented Nov 12, 2014 at 19:40
@TedHopp I thought as well, but we are restricted from doing so. — MayTheSchwartzBeWithYou
– MayTheSchwartzBeWithYou, Commented Nov 12, 2014 at 19:42

rgettman · Accepted Answer · 2014-11-12 19:44:05Z

2

Java does support boxing int to Integer, but not boxing arrays of those numeric types, e.g. it won't box int[] to Integer[].

You must convert the int[] to an Integer[] yourself before passing it to your MySortedArray<Integer> instance.

answered Nov 12, 2014 at 19:44

rgettman

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2 Comments

thanks! I still need to practice on Generics, as I always avoided them even in advanced projects.

May the ? extends Force be with you.