个笔试题-赛博商达科技

1:C程序代码片段运行后C和dInta=1,bIntcd=(a&&b)&a;publicpublicclasspublicObjectObjecto=newFloat(3.14F);//line3Object[]oa=newObject[1];//line4oa[0]=o;//line5o=null;//linereturnoa[0];//line}18.WhenistheFloatobject,createdinline3,eligibleforgarbagejustafterlinejustafterlinejustafterline7(thatis,asthemethodneverinthis1)publicvoidcreate() Vector myVect=new4) 4:ConsidertheclasshierarchyshownclassFourWheelerimplementsDrivingUtilitiesclassCarextendsFourWheelerclassTruckextendsFourWheelerclassBusextendsFourWheelerclassCraneextendsFourWheelerConsiderthefollowingcodebelow:1.DrivingUtilitiesdu;2.FourWheelerfw;TruckmyTruck=new4.du=5.fw=new6.fw6.fw=Whichofthestatementsbelowaretrue?Line4willnotcompilebecauseaninterfacecannotrefertoanThecodewillcompileandThecodewillnotcompilewithoutanexplicitcastatline6,becausegoingdownthehierarchywithoutcastingisnotallowed.Thecodewillcompileifweputanexplicitcastatline6butwillthrowanexception1.Whichisthemostappropriatecodesnippetthatcanbeinsertedatline18inthewing3.(Assumethatthecodeiscompiledandrunwithassertionsenabled)5.1.import7.9.3.publicclass{privateHashMappublic{cctld=newcctld.put("uk","United47.22.//more}//othermethodspublicStringgetCountry(String{//WhatshouldbeinsertedStringcountry=return}assertcountryCode!=assertcountryCode!=null:"Countrycodecannotbenull"assertcctld!=null:"Nocountrycodedataisassertcctld:"Nocountrycodedatais 收集能够在期望的时间释放被java7:Usetheoperator“>>”and“>>>”.WhichstatementisA.10100000000000000000000000000000>>4give000010100000000000000000B.10100000000000000000000000000000>>4give111110100000000000000000C.10100000000000000000000000000000>>>4give000000000000000000000000D.10100000000000000000000000000000>>>4give1111101000000000000000008:WhichstatementaboutthegarbagecollectionmechanismareGarbagecollectionrequireadditionalprogramecodeincaseswheremultiplethreadsarerunning.TheprogrammercanindicatethatareferencethroughalocalvariableisnolongerofTheprogrammerhasamechanismthatexplicityandimmedia yfreesthememoryusedbyJavaobjects.ThegarbagecollectionmechanismcanfreethememoryusedbyJavaObjectexplection9:JDBCJavaSQL1.1.Whatistheresultwhenyoucompileandrunthefollowingcode?3.publicclassTest5.7.publicvoidmethod()9.11.for(inti=0;i<3; pilationD.Noneof1.ThefollowingcodeisentirecontentsofafilecalledExample.java,causespreciselyeeerrorduringclassSubClassextends}classStringpublicpublicBaseClass(StringpublicclasspublicvoidSubClasss=new BaseClassb=new}}Whichlinewouldbecausethe1.1.Whatwillbetheresultofexecutingthefollowingcode?3.//Filename;SuperclassX.java5.package7.publicclassSuperclassX9.11.protectedvoidsuperclassMethodX()17.intsuperclassVarX;23.//FilenameSubclassY.java25.1.packagepackageX.packageY;29.3.publicclassSubclassYextendsSuperclassX33.5.SuperclassXobjX=newSubclassY();35.35.6.SubclassYobjY=newSubclassY();37.7.voidsubclassMethodY()43.10.inti;45.11.i=objY.superclassVarX;pilationpilationerroratline5pilationerroratlineC.RuntimeexceptionatlineD.Noneof13:WhichofthefollowingstatementsarenotA.longl=B.inti=C.doubled=D.doublet=Givethisclassclassprivateint//restofclass}AssumingthatxinvokedbythecodejavaExample,whichstatementcanmadexbedirectlyaccessibleinmain()methodofExample.java?ChangeChangeprivateintxtopublicintchangeprivateintxtostaticintChangeprivateintxtoprotectedintchangeprivateintxtofinalint15:WhichofthefollowingstatementsareTheautomaticgarbagecollectionoftheJVMpreventsprogramsfromeverrunningoutofmemoryAprogramcansuggestthatgarbagecollectionbeperformedandforceGarbagecollectionisplatformD.Ansettoeseligibleforgarbage