Convenience method to initialize mutable Set in Java

Question

Is there a convenience method to initialize a Set equivalent to Collections.singleton, which returns a mutable Set instead of an immutable one?

Answer 1

Guava is defintely a good solution.

Alternatively, you can do:

Set<T> mySet = new HashSet<>(Arrays.asList(t1, t2, t3));

Answer 2

Guava's Sets includes:

public static <E> HashSet<E> newHashSet(E... elements)

which:

Creates a mutable HashSet instance containing the given elements in unspecified order.

You can call it with a single item as:

Sets.newHashSet(item);