Efficiency of Java “Double Brace Initialization”?

Question

In Hidden Features of Java the top answer mentions Double Brace Initialization, with a very enticing syntax:

Set flavors = new HashSet         


        

Answer 1

I second Nat's answer, except I would use a loop instead of creating and immediately tossing the implicit List from asList(elements):

static public Set setOf(T ... elements) {
    Set set=new HashSet(elements.size());
    for(T elm: elements) { set.add(elm); }
    return set;
    }