question: private boolean containsMapping ( Object key , Object value ) { if ( key == null ) { HashMapEntry < K , V > e = entryForNullKey ; return e != null && Objects . equals ( value , e . value ) ; } int hash = secondaryHash ( key ) ; HashMapEntry < K , V > [ ] tab = table ; int index = hash & ( tab . length - 1 ) ; for ( HashMapEntry < K , V > e = tab [ index ] ; e != null ; e = e . next ) { if ( e . hash == hash && key . equals ( e . key ) ) { return Objects . equals ( value , e . value ) ; } } return false ; }
target:  Returns true if this map contains the specified mapping.