????1????final?? finally?? finalize??????

????final?????η??????????????????????final????ζ?????????????????μ??????????????????С?????????????????? abstract???????????final??????????????????final??????????????????в?????????????final?????????????????????????????????????????????????????????????final?????????????????????????
????finally????????????? finally ????????κ???????????????????????????????? catch ??????У??????????? finally ?饗????е??????

????finalize??????????Java ??????????? finalize() ?????????????????????????????????????????????????????????????????????????????????????б?????????????????????????? Object ???ж???????????е?????????????????? finalize() ???????????????????????????????????finalize() ????????????????????????????????????????

????2??Anonymous Inner Class (?????????) ??????extends(???)????????????implements(???)interface(???)??

?????????????????????????????????????????????????????????????????????????????????

????3??Static Nested Class ?? Inner Class???????????????(???????е?????)??

????Static nested class????????????????????static??????????????????????????????????????????Χ???????????static?????static??Ρ????????ζ???1> ?????????????????????????Χ??????2>???????????????з??????????Χ??????

????4??&??&&??????

????& ??????????????λ?????

????&&???????????????????????????????????????????????????????????????

????5??HashMap??Hashtable??????

??????????Map????????????Ω???????????????HashMap ????з??????????????????? null ?????? null ???Hashtable ?????? HashMap??????????? null ???? null ???????? HashMap ???????????????????????????

????6??Collection ?? Collections??????

????Collections???java.util?μ??????????и????й?????????????????

????Collection???java.util?μ??????????????????????

????7??List?? Set?? Map???????Collection????

????List??Set?? Map????

????8??ArrayList??Vector??????

????1>??????Vector????????????????????????ArrayList?????????????????????? 2>??????????????????????Vector????????????????ArrayList???????????

????9?????????assert??

????assertion(????)?????????????????????????????????????ж??????????????????У?assertion????????е??????????????boolean???????м?飬?????????????????boolean????????true?????????false?????????????????????????￡???????????????????????????assertion??????????????????????????assertion????????????????????????????????????????????assertion????????????

????10??GC?????? ??????GC??

????GC?????????????Java ???????????????????????????????????????й?????????????????????????????????????

System.gc() 

Runtime.getRuntime().gc()
 
????11??String s = new String("xyz")???????????String Object??

??????????????????xyx????????????xyx???????????s

????12??.Math.round(11.5)??????? Math.round(-11.5)???????

????Math.round(11.5)?????long??12??Math.round(-11.5)?????long??-11????????????????? long????????? 1/2 ???y??????????????????????????????????? long ????????仰?????????????±???????? (long)Math.floor(a + 0.5d)

????13??short s1 = 1?? s1 = s1 + 1????????? short s1 = 1?? s1 += 1?????????

????short s1 = 1?? s1 = s1 + 1????? short s1 = 1?? s1 += 1?????????short s1 = 1?? s1 = s1 + 1??????s1+1?????????????????????????????????int?????????short????s1????????????????????????????????????short s1 = 1?? s1 += 1?????? += ??java????漲?????????java???????????????????????????????????