public void setUuids(Set<String> uuids) {
    requireNonNull(uuids, "Uuids cannot be null");
    checkState(this.uuids == null, "Uuids have already been initialized");
    this.uuids = new HashSet<>(uuids);
  }
@Test
  public void fail_with_ISE_when_setting_uuids_twice() {
    assertThatThrownBy(() -> {
      sut.setUuids(newHashSet("ABCD"));
      sut.setUuids(newHashSet("EFGH"));
    })
      .isInstanceOf(IllegalStateException.class)
      .hasMessage("Uuids have already been initialized");
  }