????????Collection????????????1.2???????????
????1. ??????????HashTable?????????????????JDK 1.2?????????
????2. iterators ?? fail-fast???????????????? CRUD????
????3. serializable ?? cloneable
????4. ??????null????
????5. ???????optional methods????add??remove??????????UnsupportedOpertaionException??
????6. Set????Map??Set.add ????Map.put(SetValue?? new Object);??
????* ?????????
????heap??stack????????
?????????????μ?????????????????????????????ɡ??????????????????д????????????????????
????????Collections Framework??????
????1.  ???д???ArrayList
???????д??ArrayList??м?? AbstractList????????List??RandomAccess??Cloneable??Serializable????????????????ArryList?????д????????Collection??????????????????????д??add??get??set??size??iterator??????????????????
???????磺
????1.1 ???????ArrayList??????????????????????????????????????????????????????????????????????????????飬?????????????Copy?????????С?
????1.2 ????????????????Object?????????????Object?????????????κ?????????????????????????add?????Object[]????get?????з???????????????????????????????
???????磺return (E) elementData[index]; ( ArrayList get????????? )
????1.3 ???????????????????????getter???????????????鼰?????????????????????????????á???????????л????????????????????????????????????????????
????1.4 Iterator?????????????????getter???????б??????Щ?????
???????????????????????????????????????????????????????????е????????
?????????getter??????????????ArrayList??getter???????????return???Object[]???顣
???????Iterator??????????????????????????????????
?????磺LinkedList??HashSet???????迼????????????????????????HashMap??
????1.5 fail-fast:
??????iterator?????е????????????????????????????add??set?????????????????ConcurrentModificationException????
????fail-fast ???????????
????Martin Fowler 2004??IEEE Software???????Fail Faster??
????2.  ???Junit????
????2.1?????????????в???????????????????????????ο???????????Java ??? ?? ??Java ??????4??
????2.2????????Щ?????????????ЩЧ????????????BUG??????????磺????????NULL??????????????
???????????????????з??????磺??????  ????????????
????2.3???????????????Щ????????????????????????п???????????дtest??????????
??????????????????
????????Hash Table(????HashCode??equals)??????????
????RandomAccess??Serializable(writeObject??readObject??transient)
????Collections  ???????????
???????????????????java.util.Collections ?? java.util.Arrays??