/guava/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableBiMap.java
return new RegularImmutableBiMap<K, V> ( super.buildOrThrow ( ) ) ;
@Override public ImmutableBiMap<K, V> buildOrThrow() { ImmutableMap<K, V> map = super.buildOrThrow(); if (map.isEmpty()) { return of(); } <extra_id_0> } @Override ImmutableBiMap<K, V> buildJdkBacked() { return build(); } }