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1、本科毕业论文外文文献及译文文献、资料题目：CoreJava™VolumeII–AdvancedFeatures文献、资料来源：著作文献、资料发表（出版）日期：2008.12.1院（部）：计算机科学与技术学院专业：网络工程班级：网络082姓名：刘治华学号：2008111242指导教师：许丽娜翻译日期：2012.5.10山东建筑大学毕业论文外文文献及译文外文文献： CoreJava™VolumeII–AdvancedFeaturesWhenJavatechnologyfirstappearedonthescene,theexcitementwasnotabout
2、awell-craftedprogramminglanguagebutaboutthepossibilityofsafelyexecutingappletsthataredeliveredovertheInternet(seeVolumeI,Chapter10formoreinformationaboutapplets).Obviously,deliveringexecutableappletsispracticalonlywhentherecipientsaresurethatthecodecan'twreakhavocontheirmachines.Fo
3、rthisreason,securitywasandisamajorconcernofboththedesignersandtheusersofJavatechnology.Thismeansthatunlikeotherlanguagesandsystems,wheresecuritywasimplementedasanafterthoughtorareactiontobreak-ins,securitymechanismsareanintegralpartofJavatechnology.Threemechanismshelpensuresafety:•
4、Languagedesignfeatures(boundscheckingonarrays,nouncheckedtypeconversions,nopointerarithmetic,andsoon).•Anaccesscontrolmechanismthatcontrolswhatthecodecando(suchasfileaccess,networkaccess,andsoon).•Codesigning,wherebycodeauthorscanusestandardcryptographicalgorithmstoauthenticateJava
5、code.Then,theusersofthecodecandetermineexactlywhocreatedthecodeandwhetherthecodehasbeenalteredafteritwassigned.Below,you'llseethecryptographicalgorithmssuppliedinthejava.securitypackage,whichallowforcodesigninganduserauthentication.Aswesaidearlier,appletswerewhatstartedthecrazeover
6、theJavaplatform.Inpractice,peoplediscoveredthatalthoughtheycouldwriteanimatedappletslikethefamous"nervoustext"applet,appletscouldnotdoawholelotofusefulstuffintheJDK1.0securitymodel.Forexample,becauseappletsunderJDK1.0weresocloselysupervised,theycouldn'tdomuchgoodonacorporateintrane
7、t,eventhoughrelativelylittleriskattachestoexecutinganappletfromyourcompany'ssecureintranet.ItquicklybecamecleartoSunthatforappletstobecometrulyuseful,itwasimportantforuserstobeabletoassigndifferentlevelsofsecurity,dependingonwheretheappletoriginated.Ifanappletcomesfromatrustedsuppl
8、ierandithasnotbeentampered
