A bimap (or "bidirectional map") is a map that preserves the uniqueness ofits values as well as that of its keys. This constraint enables bimaps tosupport an "inverse view", which is another bimap containing the same entriesas this bimap but with reversed keys and values.從註釋來看,一個biMap是一個值有惟一性的Map。能夠經過inverse()方法進行key與value的反轉。若是put操做時,插入不一樣key的相同value值,那麼會拋出「Exception in thread "main" java.lang.IllegalArgumentException: value already present:」異常