Method of

guava/src/com/google/common/collect/ImmutableSet.java:82–85

Returns the empty immutable set. Preferred over {@link Collections#emptySet} for code consistency, and because the return type conveys the immutability guarantee. <p><b>Performance note:</b> the instance returned is a singleton.

()

   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings({"unchecked"}) // fully variant implementation (never actually produces any Es)
  public static <E> ImmutableSet<E> of() {
    return (ImmutableSet<E>) RegularImmutableSet.EMPTY;
  }

  /**
   * Returns an immutable set containing the given element. Preferred over {@link