????3.3 ????????????????

????1?????л??????????????CPU????Young????????и???????Old???????б???????????????Σ????mark—???sweep—???compact???????????????????????

????2?????л?????????Young?????????????л????????????????????CPU???д???? ??Old??????????л????????????????????????

????3???????????????????Young????????????л?????????????????????Old?????????????????????????????????????б?????????

?????? ??Old?????????????????

?????? mark??Σ????????У???????????

?????? summary??Σ???????У???????????????????????????????????????С??????????????????????????????????????????????????

?????? compact??Σ????????У?????????????????????????е????????????Щ?????С?????????Old???????????????????????????????????

????4?????????—????????CMS??????Young????????????л?????????????????????Old??????????????????????????????????????

?????? ??????????????????????????????????(???????)??

?????? ????????????????У??????????????????????????

?????? ???????????????????????е????±?????????????????????????????????????

?????? ????????????????У?

????4????????С????

????1????????????????eg??String javaStr = “С??????????”;

????2?????StringBuilder??StringBuffer?????????????????;

????3????????????????;

????4??????????t??????;

????5?????泣??????:?????????????????????eg??OSCache??Ehcache;

????6???????????finalize()????;

????7??????????????????????????SoftReference??