/guava/guava/src/com/google/common/collect/AbstractBiMap.java
checkArgument( forward != backward) ;checkArgument( forward.isEmpty( ) ) ;
checkArgument ( forward.isEmpty ( ) ) ;
V checkValue(@ParametricNullness V value) { return value; } void setDelegates(Map<K, V> forward, Map<V, K> backward) { checkState(delegate == null); checkState(inverse == null); <extra_id_0> checkArgument(backward.isEmpty()); checkArgument(forward != backward); delegate = forward; inverse = makeInverse(backward); } AbstractBiMap<V, K> makeInverse(Map<V, K> backward) {