2010英语java题目.doc

1.Whichstatementaboutthegarbagecollectionmechanismaretrue?A.Garbagecollectionrequireadditionalprogramecodeincaseswheremultiplethreadsarerunning.B.Theprogrammercanindicatethatareferencethroughalocalvariableisnolongerofinterest.C.TheprogrammerhasamechanismthatexplicityandimmediatelyfreesthememoryusedbyJavaobjects.D.ThegarbagecollectionmechanismcanfreethememoryusedbyJavaObjectatexplectiontime.E.Thegarbagecollectionsystemneverreclaimsmemoryfromobjectswhilearestillaccessibletorunninguserthreads.2.Givethefollowingmethod:1)publicvoidmethod()2)Stringa,b;3)a=newString(“helloworld”);4)b=newString(“gameover”);5)System.out.println(a+b+”ok”);6)a=null;7)a=b;8)System.out.println(a);9)Intheabsenceofcompileroptimization,whichistheearliestpointtheobjectareferedisdefinitelyelibiletobegarbagecollection.A.beforeline3B.beforeline5C.beforeline6D.beforeline7E.Beforeline93.Intheclassjava.awt.AWTEvent,whichistheparentclassuponwhichjdk1.1awteventsarebasedthereisamethodcalledgetIDwhichphraseaccuratelydescribesthereturnvalueofthismethod?A.Itisareferencetotheobjectdirectlyaffectedbythecauseoftheevent.B.Itisanindicationofthenatureofthecauseoftheevent.C.Itisanindicationofthepositionofthemousewhenitcausedtheevent.D.Inthecaseofamouseclick,itisanindicationofthetextunderthemouseatthetimeoftheevent.E.Ittellsthestateofcertainkeysonthekeybordatthetimeoftheevent.F.Itisanindicationofthetimeatwhichtheeventoccurred.4.Whichstatementaboutlisteneristrue?A.Mostcomponentallowmultiplelistenerstobeadded.B.Ifmultiplelistenerbeaddtoasinglecomponent,theeventonlyaffectedonelistener.C.Componentdon?tallowmultiplelistenerstobeadd.D.ThelistenermechanismallowsyoutocallanaddXxxxListenermethodasmanytimesasisneeded,specifyingasmanydifferentlistenersasyourdesignrequire.5.Givethefollowingcode:publicclassExamplepublicstaticvoidmain(Stringargs)intl=0;doSystem.out.println(“Doingitforlis:”+l);while(-l0)System.out.println(“Finish”);Whichwellbeoutput:A.Doingitforlis3B.Doingitforlis1C.Doingitforlis2D.Doingitforlis0E.Doingitforlis?C1F.Finish6.Givethecodefragment:1)switch(x)2)case1:System.out.println(“Test1”);break;3)case2:4)case3:System.out.println(“Test2”);break;5)default:System.out.println(“end”);6)whichvalueofxwouldcause“Test2”totheoutput:A.1B.2C.3D.default7.Giveincompletedmethod:1)2)if(unsafe()/dosomething3)elseif(safe()/dotheother4)Themethodunsafe()wellthroeanIOException,whichcompletesthemethodofdeclarationwhenaddedatlineone?A.publicIOExceptionmethodName()B.publicvoidmethodName()C.publicvoidmethodName()throwIOExceptionD.publicvoidmethodName()throwsIOExceptionE.publicvoidmethodName()throwsException8.Givethecodefragment:if(x4)System.out.println(“Test1”);elseif(x9)System.out.println(“Test2”);elseSystem.out.println(“Test3”);Whichrangeofvaluexwouldproduceofoutput“Test2”?A.x4C.x9D.None9.Givethefollowingmethod:publicvoidexample()tryunsafe();System.out.println(“Test1”);catch(SafeExceptione)System.out.println(“Test2”);finallySystem.out.println(“Test3”);System.out.println(“Test4”);Whichwilldisplayifmethodunsafe()runnormally?A.Test1B.Test2C.Test3D.Test410.Whichmethodyoudefineasthestartingpointofnewthreadinaclassfromwhichnewthethreadcanbeexcution?A.publicvoidstart()B.publicvoidrun()C.publicvoidint()D.publicstaticvoidmain(Stringargs)E.publicvoidrunnable()11.Giventhefollowingclassdefinition:classAprotectedinti;A(inti)this.i=i;whichofthefollowingwouldbeavalidinnerclassforthisclass?Selectallvalidanswers:A.classBB.classBextendsAC.classBextendsAB()System.out.println(“i=”+i);D.classBclassAE.classA12.Whichmodifiershouldbeappliedtoamethodforthelockofobjectthistobeobtainedpriortoexcutionanyofthemethodbody?A.synchronizedB.abstractC.finalD.staticE.public13.ThefollowingcodeisentirecontentsofafilecalledExample.java,causespreciselyoneerrorduringcompilation:1)classSubClassextendsBaseClass2)3)classBaseClass()4)Stringstr;5)publicBaseClass()6)System.out.println(“ok”);7)publicBaseClass(Strings)8)str=s;9)publicclassExample10)publicvoidmethod()11)SubClasss=newSubClass(“hello”);12)BaseClassb=newBaseClass(“world”);13)14)Whichlinewouldbecausetheerror?A.9B.10C.11D.1214.Whichstatementiscorrectlydeclareavariableawhichissuitableforreferingtoanarrayof50stringemptyobject?A.StringaB.StringaC.charaD.Stringa50F.Objecta5015.Givethefollowingjavasourcefragement:/pointxpublicclassInteresting/dosomethingWhichstatementiscorrectlyJavasyntaxatpointx?A.importjava.awt.*;B.packagemypackageC.staticintPI=3.14D.publicclassMyClass/dootherthingE.classMyClass/dosomething16.Givethisclassoutline:classExampleprivateintx;/restofclassbodyAssumingthatxinvokedbythecodejavaExample,whichstatementcanmadexbedirectlyaccessibleinmain()methodofExample.java?A.ChangeprivateintxtopublicintxB.changeprivateintxtostaticintxC.ChangeprivateintxtoprotectedintxD.changeprivateintxtofinalintx17.thepieceofpreliminaryanalsisworkdescribesaclassthatwillbeusedfrequentlyinmanyunrelatedpartsofaproject“Thepolygonobjectisadrawable,Apolygonhasvertexinformationstoredinavector,acolor,lengthandwidth.”WhichDatatypewouldbeused?A.VectorB.intC.StringD.ColorE.Date18.Aclassdesignrequiresthatamembervariableshouldbeaccessibleonlybysamepackage,whichmodiferwordshouldbeused?A.protectedB.publicC.nomodiferD.private19.Whichdeclaresfornativemethodinajavaclasscorrected?A.publicnativevoidmethod()B.publicnativevoidmethod();C.publicnativemethod();D.publicvoidmethod()native;E.publicvoidnativemethod();20.Whichmodifershouldbeappliedtoadeclarationofaclassmembervariableforthevalueofvariabletoremainconstantafterthecreationoftheobject?21.Whichisthemain()methodreturnofaapplication?A.StringB.byteC.charD.void22.Whichiscorrectedargumentofmain()methodofapplication?A.StringargsB.StringarC.CharargsD.StringBufferarg23.“TheEmployeeobjectisaperson,AnEmployeehasappointmentstoreinavector,ahiredateandanumberofdependent”shortanswer:useshorteststatementdeclareaclassofEmployee.24.Givethefollowingclassdefinationinseparatesourcefiles:publicclassExamplepublicExample()/dosomethingprotectedExample(inti)/dosomethingprotectedvoidmethod()/dosomethingpublicclassHelloextendsExample/membermethodandmembervariableWhichmethodsarecorrectedaddedtotheclassHello?A.publicvoidExample()B.publicvoidmethod()C.protectedvoidmethod()D.privatevoidmethod()25.Floats=newFloat(0.9F);Floatt=newFloat(0.9F);Doubleu=newDouble(0.9);Whichexpression?sresultistrue?A.s=tB.s.equals(t)C.s=uD.t.equals(u)26.Givefollowingclass:classAClassprivatelongval;publicAClass(longv)val=v;publicstaticvoidmain(Stringargs)AClassx=newAClass(10L);AClassy=newAClass(10L);AClassz=y;longa=10L;intb=10;Whichexpressionresultistrue?A.a=b;B.a=x;C.y=z;D.x=y;E.a=10.0;27.Asocketobjecthasbeencreatedandconnectedtoastandardinternetserviceonaremotenetworkserver.WhichconstructiongivethemostsuitablemeansforreadingASCIIdataonlineatatimefromthesocket?A.InputStreamin=s.getInputStream();B.DataInputStreamin=newDataInputstream(s.getInputStream();C.ByteArrayInputStreamin=newByteArrayInputStream(s.getInputStream();D.BufferedReaderin=newBufferedReader(newInputStreamReader(s.getInputStream();E.BufferedReaderin=newBufferedReader(newInputStreamReader(s.getInputStream(),”8859-1”);28.Strings=”ExampleString”;Whichoperationislegal?A.s=3;B.inti=s.length();C.s3=”x”;D.Stringshort_s=s.trim();E.Stringt=”root”+s;29.Whathappenswhenyoutrytocompileandrunthefollowingprogram?classMysteryStrings;publicstaticvoidmain(Stringargs)Mysterym=newMystery();m.go();voidMystery()s=”constructor”;voidgo()System.out.println(s);A.thiscodewillnotcompileB.thiscodecomplilesbutthrowsanexceptionatruntimeC.thiscoderunsbutnothingappearsinthestandardoutputD.thiscoderunsand“constructor”inthestandardoutputE.thiscoderunsandwrites”null”inthestandardoutput30.WhatusetopositionaButtoninaFrame,onlywidthofButtonisaffectedbytheFramesize,whichLayoutButtonwellbeset?A.FlowLayout;B.GridLayout;C.NorthofBorderLayoutD.SouthofBorderLayoutE.EastorWestofBorderLayout31.WhatusetopositionaButtoninaFrame,sizeofButtonisnotaffectedbytheFramesize,whichLayoutButtonwillbeset?A.FlowLayout;B.GridLayout;C.NorthofBorderLayoutD.SouthofBorderLayoutE.EastorWestofBorderLayout32.AnAWTGUIunderexposurecondition,whichoneormoremethodwellbeinvokewhenitredraw?A.paint();B.update();C.repaint();D.drawing();33.SelectvalididentifierofJava:A.userNameB.%passwdC.3d_gameD.$chargeE.this34.WhichareJavakeyword?A.gotoB.nullC.FALSED.nativeE.const35.Runacorrectedclass:java?CcsAClassabcWhichstatementistrue?A.args0=”-cs”;B.args1=”abc”;C.args0=”java”;D.args0=”a”;E.args1=?b?36.Givethefollowingjavaclass:publicclassExamplestaticintx=newint15;publicstaticvoidmain(Stringargs)System.out.println(x5);Whichstatementiscorrected?A.Whencompile,someerrorwilloccur.B.Whenrun,someerrorwilloccur.C.Outputiszero.D.Outputisnull.37.Givethefollowingjavaclass:publicclassExamplepublicstaticvoidmain(Stringargs)staticintx=newint15;System.out.println(x5);Whichstatementiscorrected?A.Whencompile,someerrorwilloccur.B.Whenrun,someerrorwilloccur.C.Outputiszero.D.Outputisnull.38.Shortanswer:Thedecimalvalueofiis12,theoctalivalueis:39.Shortanswer:Thedecimalvalueofiis7,thehexadecimalivalueis:40.Whichistherangeofchar?A.2727-1B.0216-1C.0216D.02841.Whichistherangeofinttype?A.-216216-1B.-231231-1C.-232232-1D.-264264-142.Givethefollowingclass:publicclassExampleStringstr=newString(“good”);charch=publicstaticvoidmain(Stringargs)Exampleex=newExample();ex.change(ex.str,ex.ch);System.out.println(ex.str+”and”+ex.ch);publicvoidchange(Stringstr,charch)str=”testok”;ch0=?g?Whichistheoutput:A.goodandabcB.goodandgbcC.testokandabcD.testokandgbc43.WhichcodefragmentswouldcorrectlyidentifythenumberofargumentspassedviacommandlinetoaJavaapplication,excludethenameoftheclassthatisbeinginvoke.A.i