/guava/guava/src/com/google/common/collect/HashBiMap.java
this.firstInKeyInsertionOrder = null;entry.prevInKeyInsertionOrder = null;
entry.prevInKeyInsertionOrder = null;
public V remove(@CheckForNull Object key) { BiEntry<K, V> entry = seekByKey(key, smearedHash(key)); if (entry == null) { return null; } else { delete(entry); <extra_id_0> entry.nextInKeyInsertionOrder = null; return entry.value; } } @Override public void clear() {