QUESTION121

Given:

10.classLine{

11publicstaticclassPoint{}

12.}

13.

14.classTriangle￡

15//insertcodehere

16.}

Whichcode,insertedatline15,createsaninstanceofthePointclassdefinedinLine?

A.Pointp=newPoint();

B.Line.Pointp=newLine.point();

C.ThePointclasscannotbeinstatiatedatline15.

D.Line1=newLine();1.Pointp=newl.Point();

Answer:(B)

靜態內部類創建方法非靜態內部類的構造：Line.Pointp=newLine().newPoint();

參考大綱：面向對象一內部靜態類

QUESTION122

Given:

publicclassPlant(

privateStringna?e.

3.publicPlant(Stringna.Me){thisnane■naae,)

4.publicString9etN?Me(){return

5.}

LpublicclassTreeextendsPlant{

publicvoidgrovFzuit(){}

publicvoiddropLe>vec>()《}

4}

Whichstatementistrue?

A.Thecodewillcompilewithoutchanges.

B.ThecodewillcompileifpublicTree(){Plant();}isaddedtotheTreeclass.

C.ThecodewillcompileifpublicPlant(){Tree();}isaddedtothePlantclass.

D.ThecodewillcompileifpublicPlant(){this(nfern");}isaddedtothePlantclass.

E.ThecodewillcompileifpublicPlant(){Plant(Mfern");}isaddedtothePlantclass.

Answer:(D)

子類默認調用父類無參構造函數，而Plant沒有無參構造函數，因此須顯示調用有參構造函數

參考大綱：面向對象

QUESTION123

Given:

10publicclassBar(

11staticvoidfoo(int...x){

12〃insertcodehere

13)

14)

Whichtwocodefragments,insertedindependentlyatline12,willallowtheclasstocompile?(Choose

two.)

A.foreach(x)System.out.print1n(z);

B.for(intz:x)System.out.print1n(z);

C.while(x.hashNext())System.out.print1n(x.next())

D.for(inti=0;i<x.length;i++)System.out.println(x[i]);

Answer:(B,D)

可變參數方法編譯后變成數組參數方法，然后利用循環結構取出數組的值

參考大綱：流程控制和可變長度參數

QUESTION124

Exhibit:

1publicinterfaceA{

2publicvoiddoSoaething(Stringthing);

3.}

1publicclassAlMpliMpleaientsA{

2.publicvoiddoSonothing(Stringasg){}

3.}

1publicclassB{

2publicAdoit(){

3?//morecodehere

4.}

6publicStringexecute(){

7.//acrecodehere

8.}

9.}

1publicclassCextenorB{

2publicAlapldoit(){

3,//morecodehere

4.>

6publicObjectexecute(){

7.//aorecodehere

8.)

9.}

Whichstatementistrueabouttheclassesandinterfacesintheexhibit?

A.Compilationwillsucceedforallclassesandinterfaces.

B.CompilationofclassCwillfailbecauseofanerrorinline2.

C.CompilationofclassCwillfailbecauseofanerrorinline6.

D.CompilationofclassAlmplwillfailbecauseofanerrorinline2.

Answer:(C)

參考大綱：面向對象一復寫

QUESTION125

Placethelinesinthecorrectordertocompletetheenum。

enumElement{

Answer:()

enumElement{

EARTH,WIND,

FIRE{

publicStringinfo(){return"Hot”;}

)；

publicStringinfo(){return“element”;}

)

列舉的內容之后要加上“產

參考大綱：面向對象一enum

QUESTION126

PlacethecodeelementsinordersothattheresultingJavasourcefilewillcompile

correctly,resultinginaclasscalledcom.sun.cert.AddressBook.

SourceFileCodeElement

packageoomsuncert;

packagecomsun.cer*.

importjavauttl

importjava

publicclassAddressBook{

publicstaticclassAddressBook{

Answer:()

packagecom.sum.cert;

importjava.util.*;

publicclassAddressBook{

ArrayListentries;

)

參考大綱：面向對象一語法基礎

QUESTION127

Whichtwoclassescorrectlyimplementboththejava.lang.Runnableandthe

javaJang.Clonableinterfaces?(Choosetwo.)

A.publicclassSessionimplementsRunnable,Clonable{

publicvoidrun();

publicObjectclone();

)

B.publicclassSessionextendsRunnable,Clonable{

publicvoidrun(){/*dosomething*/}

publicObjectclone。{/*makeacopy*/}

)

C.publicclassSessionimplementsRunnable,Clonable{

publicvoidrun(){/*dosomething*/}

publicObjectclone(){/*makeacopy*/)

)

D.publicabstractclassSessionimplementsRunnable,Clonable{

publicvoidrun(){/*dosomething*/}

publicObjectclone(){/*makeacopy*/}

E.publicclassSessionimplementsRunnable,implementsClonable{

publicvoidrun(){/*dosomething*/)

publicObjectclone(){/*makeacopy*/}

Answer:(C,D)

A錯誤Session是具體類，方法必須實現

B實現interface用implemenls

C正確

D正確

E錯誤implements只能出現一次

參考大綱：多線程

QUESTION128

Given:

1classClassA(

2publiciatnuaberOfInstances,

3protectedClassA(intnixaberOfInstances)<

4thi?onuaberOfInstances-nuaberOfInstances

S)

6.)

7publicclassExtendedAextencrsClassA{

8privateExtended!(mtnuaberOfInstances){

9super(nuaberOfInstances);

10.)

11publicstaticvoidMain(String[Jargs)(

12ExtendedAext■newExtendedA(420);

13Systemoutprint(extnuaberOfInstances);

14.1

15.}

Whichstatementistrue?

A.420istheoutput

B.Anexceptionisthrownatruntime.

C.Allconstructorsmustbedeclaredpublic.

D.ConstructorsCANNOTusetheprivatemodifier.

E.ConstructorsCANNOTusetheprotectedmodifier.

Answer:(A)

參考大綱：面向對象

QUESTION129

Given:

1

2publicclassBase{

3publicstaticfinalStringFOO**foo*;

4publicstaticvoidA5in(String[]args){

5baseb■newHase();

6Subs?newSub();

7Systemoutprint(BaseFOO);

8Systemout.print(SubFOO);

9SystCMoutprint(bFOO)：

0Systemout.print(sFOO);

1Systemout.print(((Base)s)FOO);

2}}

classSubextendsBase{publicstaticfinalStringFOO"-bar";}

Whatistheresult?

A.foofoofoofoofbo

B.fbobarfbobarbar

C.foobarfoofoofoo

D.foobarfoobarfoo

E.barbarbarbarbar

F.foofoofoobarbar

G.fbofbofbobarfbo

Answer:(D)

參考大綱：面向對象一屬性的重載和遮蔽，該題中子類遮蔽了父類的屬性

QUESTION130

Whichtwostatementsaretrueabouthas-aandis-arelationships?(Choosetwo.)

A.Inheritancerepresentsanis-arelationship.

B.Inheritancerepresentsanhas-arelationship.

C.Interfacesmustbeusewhencreatingahas-arelationship.

D.Instancevariablescanbeusedwhencreatingahas-arelationship.

Answer:(A,D)

參考大綱：面向對象

QUESTION131--------

Given:

1.packagegeoaetry:

2.publicclassHypotenuse{

3.publicInnerTriangleit-newInnerTriangle();

4classInnerTriangle{

5.publicintbase.

6.publicintheight:

7}

8.}

Whichstatementistrueabouttheclassofanobjectthatcanreferencethevariablebase?

A.Itcanbeanyclass.

B.Noclasshasaccesstobase.

C.Theclassmustbelongtothegeometrypackage.

D.TheclassmustbeasubclassoftheclassHypotenuse.

Answer:(C)

參考大綱：面向對象

QUESTION132

Given:

classA(

Stringnaae■"A";

StringgetName(){

returnnaae;

)

Stringgreeting(){

return"classA";

)

)

classBextendsA{

Stringnaae■"BM;

Strinsinc<(){

return"classB";

)

},

publicclassClient(

publicstaticvoidaam(String1]args){

AQ?newA().

Ab-newB();

Systemoutprintln(agreeting()?"hasname"+agetName());

Systeaoutprintln(bgreeting()+“hasnaae*+bgetNaMe());

)

}

Placethenames"A"and"B"inthefollowingoutput.

Names

class|PUcehr6]hasname[Raceher.1

class[Placehe(Nhasna?e|Raceherr]

Answer:()

class|AhasnaaeA

class|B1hasnameA

參考大綱：面向對象classBhasnameA

QUESTION133

Given:

1.interfaceA{publicvoidaMethcxi();)

2.interfaceB{publicvoidbMethod();}

3.interfaceCextendsA.B{publicvoidcMethod().}

4classDiMplenentsB(

S.publicvoidbMethcxi(){}

6.}

7classEextendsDlaplenentsC{

8publicvoidaMethod(){}

9publicvoidbMethod(){}

10.、publicvoidcMethod()0

11.)

Whatistheresult?

A.Compilationfailsbecauseofanerrorinline3.

B.Compilationfailsbecauseofanerrorinline7.

C.Compilationfailsbecauseofanerrorinline9.

D.IfyoudefineDe=newE(),thene.bMethod()invokestheversionofbMethod()

definedinline5.

E.IfyoudefineDe=(D)(newE()),thene.bMethod()invokestheversionofbMethod()

definedinline5.

F.IfyoudefineDe=(D)(newE()),thene.bMethod()invokestheversionofbMethod()

definedinline9.

Answer:(F)E類的對象調用b.Method(),因為E類體里有這個方法就遮蔽了父類的方法

參考大綱：面向對象

QUESTION134

Whichtwostatementsaretrue?(Choosetwo.)

A.Anencapsulation,publicclasspromotesre-use.

B.Classesthatsharethesameinterfacearealwaystightlyencapsulated.

C.Anencapsulatedclassallowssubclassestooverloadmethods,butdoesNOTallow

overridingmethods.

D.Anencapsulatedclassallowsprogrammertochangeanimplementationwithout

affectingoutsidecode.

Answer:(A,D)

參考大綱：面向對象

QUESTION135--BT

PlacetheRelationsontheircorrespondingImplementationStructures.

Note:NotallImplementationStructreswillbeused.

Relations

ImplementationStructures

CarisVehicle

classA{And

classA

List<B>b;CarisaCollectable

extendsB.C{}

Carhasa

SteeringTVheel

classA(

classA{}Be.Cc;

)

CarhasWheels

classA{classA

Bb;implementsB.C

{}MiniisaCar

classA

CarisanObject

extendsB{)

Answer:()

Relations

ImplementationStructures

CarisVehicle

And

classA

CarhasWheelsCarisaCollectable

extendsB.C[}

Carhasa

SteeringWheel

classA{

CarisanObjectBc;Cc;

CarhasWheels

GarisVehicle

CarhasaAnd

SteeringTVheel

CarisaCollectableMinitsaCar

MiniisaCarCarisanObject

參考大綱：面向對象

QUESTION136

Given:

10

11publicclassHello(

12Stringtitle;

13intvalue.

14publicHello(){

M

15titleWorld";

16)

17publicHello(intvalue){

18thisvalue?value;

19title-"Hello";

20Heilo():

21)

)

And:

30:Helloc-newHello(5);

31:Systeaoutprmtln(ctitle);

Whatistheresult?

A.Hello

B.HelloWorld

C.Compilationfails.

D.HelloWorld5

E.Thecoderunswithnooutput.

F.Anexceptionisthrownatruntime.

Answer:(C)

19行應改為this。應該放在第一行；

參考大綱：面向對象

QUESTION137-

Given:

1.classSuper{

2.privateinta.

3.protectedSuper(inta){thisa?a;}

4}

11classSubextendsSuper{

12.publicSub(inta){super(a);}

13.publicSub()(thxAa?E;)

14}

Whichtwo,independently,willallowSubtocompile?(Choosetwo.)

A.Changeline2to:publicinta;

B.Changeline2to:protectedinta;

C.Changeline13to:publicSub(){this(5);}

D.Changeline13to:publicSub(){super(5);J

E.Changeline13to:publicSub(){super(a);}

Answer:(C,D)

參考大綱：面向對象

QUESTION138-

classConverter{

publicstaticvoidxain(Striag[]args){

Integeri■args[0];

intj■12,

Systea.outprintlndt+“that")

)?

)

Whatistheresultwhentheprogrammerattemptstocompilethecodeandrunitwiththecommand：

javaConverter12?

A.Itistruethatj=i.

B.Itisfalsethatj==i.

C.Anexceptionisthrownatruntime.

D.Compilationfailsbecauseofanerrorinline13.

Answer:(D)

參考大綱：語言基礎

QUESTION139

Given:

1.publicclasslestStringl{

2publicstaticvoid?&m(Strin9[]args){

3Stringstr?3420".

4.str42;

5.Systemoutprint(str);

Whatistheoutput?

A.42

B.420

C.462

D.42042

E.Compilationfails

F.Anexceptionisthrownatruntime.

Answer:(D)

參考大綱：語言基礎

QUESTION140-BT

AssumingthattheserializeBanana2()andthedeserializeBanana2()methodswill

correctlyuseJavaserializationandgiven:

importjava.io.

classFood{Food(){Systea.out.print("1");}}

classFruitextendsFoodiMpleMentsSerializable{

Fruit(){Systewoutprint("2");}}

publicclassBanana2extendsFruit{intsize?42;

publicstaticvoidAain(String[]args){

2oBanana2b=newBanana2();

21b.serializeBanana2(b);〃assuaecorrectserialization

bBb.deserializeBanana2(b);//assuxecorrsct

22.System.out.println("restored"+b.size+"”)；}

23.〃moreBanana2Methods

24.}

Whatistheresult?

A.Compilationfails

B.1restored42

C.12restored42

D.121restored42

E.1212restored42

F.Anexceptionisthrownatruntime

Answer:(D)

因為父類Food未實現serializable接口，反序列化時將調用Food的構造函數,見工程執行結果

參考大綱：IO操作一序列化機制

QUESTION141

Given:

11.Stringtest**alb2c3";

12.String1]tokens■testsplit("wd*);

13for(^trinqs:tokens)Svste?outprint(s+.");

Whatistheresult?

A.abc

B.123

C.alb2c3

D.alb2c3

E.Compilationfails

F.Thecoderunswithnooutput.

G.Anexceptionisthrownatruntime.

Answer:(A)

參考大綱：實用API

QUESTION142

Given:

12Stringcsv■"Sue,5.true,3"

13Scannerscanner■newScanner(csv);

14scanneruseDeliMiter("/);

19intage?scannernextlntO

Whatistheresult?

A.Compilationfails

B.Afterline15,thevalueofageis5.

C.Afterline15,thevalueofageis3.

D.Anexceptionisthrownatruntime.

Answer:(D)

拋出java.util.InputMismatchException異常

正確讀取方法：

scaner.next();

scaner.nextlnt();

scaner.nextBoolean();

scaner.nextlnt();

參考大綱：實用API—Scanner簡易I/O工具

QUESTION143

GivenavalidDateFormatobjectnameddf,and

16Dated■newDate(OL);

17.Stringds""December15.2004*;

IB.//insertcodehere

Whatupdatesd'svaluewiththedaterepresentedbyds?

A.18.d=^parse(ds);

B[&d=叟就2輾儂)，

C18fry(

19.d=度1里;

20)catch住勿e){}；

D.18.蛭{

19.d=d￡getDate(ds);

20}catch便延wwE甚￡版奧Re)();

A.A

B.B

C.C

D.D

Answer:(C)

DateFormat類的parse(Strings)會拋ParsnException異常.

參考大綱：實用API—DataFormat

QUESTION144

PlacetheFragmentsintotheprogram,sothattheprogramwillgetlinesfromatextfile,displaythem,

andthenclosealltheresources.

CodeFragments

import}ava10?

publicclassReadFile(

publicstaticvoidMaxn(Stnng[)args){

File[7]?newFile(?MyTexttxf),

|?|"nevMacehere(xl)：

Placeherex4?new(x2).

Strm9x3?null...

while((x3■|Rtceherf]())l?null){

Systemout.

>rH「POcehete]().

)catch(Exceptionex){EDdU

exprintStAckTrace().

)(33(HI

)

Answer:()

CodeFragments

import^ava10?

publicclassReadFile(

publicstaticvoidMain(Strmg[]args){

File(WTextUct?)

m-nev[PieReader](xl)

/4-nev|6ulfered^eader|(*2)：

Stringx3"null.

vhxle((x3-四匚readLme]1(>>I?null){

Systsout3);

}[H]idose;

}cetch(Exceptionex){

exprintStackTrace();[xTirsri

)

}

參考大綱：IO操作

QUESTION145

Given:

1.publicclassTarget{

2.privateinti?0;

3.publicmtaddOnef){

4return4-41

5.)

?

And:

1.publicclassClient(

2.publicstaticvoidMain(String[]args){

3Systeaoutprintln(nevTarget().addOne());

4}

5.)

WhichchangescanyoumaketoTargetwithoutaffectingClient?

A.Line4ofclassTargetcanbechangedtoreturni++;

B.Line2ofclassTargetcanbechangedtoprivateinti=1;

C.Line3ofclassTargetcanbechangedtoprivateintaddOne(){

D.Line2ofclassTargetcanbechangedtoprivateIntegeri=0;

Answer:(D)

A:return++i;和returni++;不一樣.

參考大綱：實用API

QUESTION146

Given:

1classSuperClass(

2.publicAgetA(){

3.returnnewA();

4.>

5.?

6.classSubClassextendsSuperClass(

7.publicBgetAf){

8.returnnevB()?

9.}

10.)

Whichstatementistrue?

A.CompilationwillsucceedifAextendsB.

B.CompilationwillsucceedifBextendsA.

C.Compilationwillalwaysfailbecauseofanerrorinline7.

D.Compilationwillalwaysfailbecauseofanerrorinline8.

Answer:(B)

參考大綱：面向對象一重寫

QUESTION147

Given:

1

2classPizza{

3javautilArrayListtoppings.

4publicfinalvoidaddToppmg(Stringtopping){

5toppings.add(topping);

6}

7)

8publicclassPopperonlPizzaextendsPizza{

9publicvoidaddTopping(btringtopping){

10Systeaoutprintln("CannotaddToppings*)

11}

12publicstaticvoidMain(String[]args)(

13Pizzapizza-newPepperoniPizza();

14pizza.addTopping("HushrooMs"):

15}

?

Whatistheresult?

A.Compilationfails.

B.CannotaddToppings

C.Thecoderunswithnooutput.

D.ANullPointerExceptionisthrowninLine4.

Answer:(A)

final方法不能重寫

參考大綱：面向對象

QUESTION148

Insertsixmodifiersintothecodesuchthatitmeetsalloftheserequirements:

1ItmustbepossibletocreateinstancesofAlphaandBetafromoutsidethepackagesinwhich

theyaredefined

2WhenanobjectoftypeAlpha(oranypotentialsubclassofAlpha)hasbeencreated.

theinstancevanablealphamayneverbechanged

3ThevalueoftheinstancevanablealphamustalwaysbeWforobjectsoftypeAlpha

CodeModifiers

packagealpha

Ftocehif]classAlpha{IgwI

Plxehoe]Stringalpha.

[Ptocej"]Alpha()(thxsCA*).}

[Pteceher^~1Alpha(Stringa)<alpha?a;)II

packagebeta;

PtocehwjclassBetaextendsalphaAlpha{

|PUcehe?e]BetaCStringa){super(ai).)

|

Answer:()

2,4,8,9行符合條件一;3行符合條件二;5行符合條件三.

1ItmustbepossibletocreateinstancesofAlphaandBetafromoutsidethepackagesinwhich

theyaredefined

2WhenanobjectoftypeAlpha(oranypotentialsubclassofAlpha)hasbeencreated,

theinstancevanablealphamayneverbechanged

3Thevalueoftheinstancevanablealphamustalwaysbe"A"forobjectsoftypeAlpha

CodeModifiers

packagealpha.

j巾classAlpha(

StringAlpha;

Alpha(){this(-A");}

AlphaCStringa)(alpha?a.}

paukaa。beta.

[[classBetaextendsAlpha(

|[Beta(Strin9a){super(a).)

參考大綱：語言基礎一存取權限

QUESTION149

Given:

10.interfaceA{voidx();}

11classBinpleMentsA{publicvoidx(){}publicvoidy()<}>

12classCextendsB{publicvoidx(){}}

Annd:

20

213avautilIist<A>list■newjava.util.ArraLyList<A>();

22list.add(nevB());

23listadd(newC());

24fox(Aa:list){

25ax(),

26ay()

}

Whatistheresult?

A.Thecodenanswithnooutput.

B.Anexceptionisthrownatruntime.

C.Compilationfailsbecauseofanerrorinline20.

D.Compilationfailsbecauseofanerrorinline21.

E.Compilationfailsbecauseofanerrorinline23.

F.Compilationfailsbecauseofanerrorinline25.

Answer:(F)

a對象沒有y()方法

參考大綱：面向對象

QUESTION150

Aprogrammerneedstocreatealoggingmethodthatcanacceptanarbitrary

numberofarguments.Forexample,itmaybecalledintheseways:

logit("logaessagel*);

logit("logmessage2*."logaessage3");

loglt("logmessage4""logmessages""loamessaaeSN}

Whichdeclarationsatisfiesthisrequirement?

A.publicvoidlog!t(String*msgs)

B.publicvoidloglt(String[]msgs)

C.publicvoidloglt(String...msgs)

D.publicvoidlogIt(Stringmsgl,Stringmsg2,Stringmsg3)

Answer:(C)

參考大綱：面向對象可變參數

QUESTION151-----------------------------------

Exhibit:

1

2classPerson!

3Stringnaae?"Nonaae**;

4publicPerson(StringHB){naae?na,}

5}

6

7classEaployeeextendsPerson{

8StringenpID?"0000".

dpublicEitployee(Stringid){eapID

9

0)

1

2publicclassEmployeeTest(

publicstaticvoxdMam(btring[]ar^s)

3

4Eaployeee■nevEaployeeC-4321");

5Systeaout.prmtln(eeapID);

6}

}

Whatistheresult?

A.4321

B.0000

C.Anexceptionisthrownatruntime.

D.Compilationfailsbecauseofanerrorinline18.

Answer:(D)

父類沒有無參構造函數

參考大綱：面向對象

QUESTION152

Given:

11publicclassBall(

12publicenuMColor{RED.GREEN.BLUE);

13publicvoidfoo(){

14//insertcodehere

15{Systan.outprintIn(c);)

16.)

17.}

Whichcodeinsertedatline14causesthefoomethodtoprintRED,GREEN,andBLUE?

A.for(Colorc:Color.values())

B.for(Colorc=RED;c<=BLUE;C++)

C.for(Colorc;c.hasNext();c.next()}

D.for(Colorc:Color[0];c<=Color[2];C++)

E.for(Colorc:Color[0];c<=Color.BLUE;C++)

Answer:(A)

enumColorextendsEnum{};

Eiwm類的子類有values。,可以返回子類的數組.

參考大綱：面向對象一enum

QUESTION153

Exhibit:

1publicclassA(

2.

3.privateintcounter?0;

4

5.publicstaticintgetlnstanceCount()<

6.returncounter,

7.}

8.

9,publicA(){

10.counter-M-;

11.)

12.

13.)

GiventhiscodefromClassB:

25

26Aal-newA();

27Aa2-newA().

28Aa3-newk();

Systemoutpnntln(AgetlnstanceCount());

Whatistheresult?

A.CompilationofclassAfails.

B.Line28printsthevalue3toSystem.out.

C.Line28printsthevalue1toSystem.out.

D.Aruntimeerroroccurswhenline25executes.

E.Compilationfailsbecauseofanerrorinline28.

Answer:(A)

第6行錯誤

參考大綱：面向對象

QUESTION154

Given:

10classOne{

11voidfoo(){}

12>

13classTwoextendsOne{

14Z-zinsertBethodheire

15)

Whichthreemethods,insertedindividuallyatline14,willcorrectlycompleteclassTwo?

(Choosethree.)

A.intfoo(){/*morecodehere*/}

B.voidfoo(){/*morecodehere*/}

C.publicvoidfoo(){/*morecodehere*/}

D.privatevoidfoo(){/*morecodehere*/}

E.protectedvoidfoo(){/*more