question: @ Override public V put ( K key , V value ) { poll ( ) ; int index = 0 ; Entry < K , V > entry ; if ( key != null ) { index = ( Collections . secondaryHash ( key ) & 0x7FFFFFFF ) % elementData . length ; entry = elementData [ index ] ; while ( entry != null && ! key . equals ( entry . get ( ) ) ) { entry = entry . next ; } } else { entry = elementData [ 0 ] ; while ( entry != null && ! entry . isNull ) { entry = entry . next ; } } if ( entry == null ) { modCount ++ ; if ( ++ elementCount > threshold ) { rehash ( ) ; index = key == null ? 0 : ( Collections . secondaryHash ( key ) & 0x7FFFFFFF ) % elementData . length ; } entry = new Entry < K , V > ( key , value , referenceQueue ) ; entry . next = elementData [ index ] ; elementData [ index ] = entry ; return null ; } V result = entry . value ; entry . value = value ; return result ; }
target:  Maps the specified key to the specified value.