guava/src/com/google/common/collect/ImmutableBiMap.java
public static <K, V> ImmutableBiMap<K, V> of(K k1, V v1, K k2, V v2) {
    return RegularImmutableBiMap.fromEntries(entryOf(k1, v1), entryOf(k2, v2));
  }
public static <K, V> ImmutableBiMap<K, V> of(K k1, V v1, K k2, V v2) {
    return RegularImmutableBiMap.fromEntries(entryOf(k1, v1), entryOf(k2, v2));
  }
public static < K , V > ImmutableBiMap < K , V > of ( K k1 , V v1 , K k2 , V v2 ) { return RegularImmutableBiMap . fromEntries ( entryOf ( k1 , v1 ) , entryOf ( k2 , v2 ) ) ; }
Returns an immutable map containing the given entries, in order.

@throws IllegalArgumentException if duplicate keys or values are added
Returns an immutable map containing the given entries in order .