android/guava/src/com/google/common/graph/EndpointPair.java
public static <N> EndpointPair<N> unordered(N nodeU, N nodeV) {
    // Swap nodes on purpose to prevent callers from relying on the "ordering" of an unordered pair.
    return new Unordered<N>(nodeV, nodeU);
  }
public static <N> EndpointPair<N> unordered(N nodeU, N nodeV) {
    // Swap nodes on purpose to prevent callers from relying on the "ordering" of an unordered pair.
    return new Unordered<N>(nodeV, nodeU);
  }
Returns an {@link EndpointPair} representing the endpoints of an undirected edge.