SCJP認(rèn)證試題及答案

轉(zhuǎn)載對(duì)題目和答案謹(jǐn)做參考

Q1

Amethodis...

1)animplementationofanabstraction.

2)anattributedefiningthepropertyofaparticularabstraction.

3)acategoryofobjects.

4)anoperationdefiningthebehaviorforaparticularabstraction.

5)ablueprintformakingoperations.

Q2

Anobjectis...

1)whatclassesareinstantiatedfrom.

2)aninstanceofaclass.

3)ablueprintforcreatingconcreterealizationofabstractions.

4)areferencetoanattribute.

5)avariable.

Q3

Whichlinecontainsaconstructorinthisclassdefinition?

publicclassCounter{//(1)

intcurrent,step;

publicCounter(intstartValue,intstepValue){//(2)

set(startValue);

setStepValue(stepValue);

}

publicintget(){returncurrent;}//(3)

publicvoidset(intvalue){current=value;}//(4)

publicvoidsetStepValue(intstepValue){step=stepValue;}//(5)

}

1)Codemarkedwith(1)isaconstructor

2)Codemarkedwith(2)isaconstructor

3)Codemarkedwith(3)isaconstructor

4)Codemarkedwith(4)isaconstructor

5)Codemarkedwith(5)isaConstructor

Q4

GiventhatThingisaclass,howmanyobjectsandreferencevariablesarecreatedbythefollowingcode?

Thingitem,stuff;

item=newThing();

Thingentity=newThing();

1)Oneobjectiscreated

2)Twoobjectsarecreated

3)Threeobjectsarecreated

4)Onereferencevariableiscreated

5)Tworeferencevariablesarecreated

6)Threereferencevariablesarecreated.

Q5

Aninstancemember…

1)isalsocalledastaticmember

2)isalwaysavariable

3)isneveramethod

4)belongstoasingleinstance,nottotheclassasawhole

5)alwaysrepresentsanoperation

Q6

HowdoobjectspassmessagesinJava?

1)Theypassmessagesbymodifyingeachother'smembervariables

2)Theypassmessagesbymodifyingthestaticmembervariablesofeachother'sclasses

3)Theypassmessagesbycallingeachother'sinstancemembermethods

4)Theypassmessagesbycallingstaticmembermethodsofeachother'sclasses.

Q7

Giventhefollowingcode,whichstatementsaretrue?

classA{

intvalue1;

}

classBextendsA{

intvalue2;

}

1)ClassAextendsclassB.

2)ClassBisthesuperclassofclassA.

3)ClassAinheritsfromclassB.

4)ClassBisasubclassofclassA.

5)ObjectsofclassAhaveamembervariablenamedvalue2.

Q8

IfthissourcecodeiscontainedinafilecalledSmallProg.java,whatcommandshouldbeusedtocompileitusingtheJDK?

publicclassSmallProg{

publicstaticvoidmain(Stringargs[]){System.out.println("Goodluck!");}

}

1)javaSmallProg

2)avacSmallProg

3)javaSmallProg.java

4)javacSmallProg.java

5)javaSmallProgmain

Q9

Giventhefollowingclass,whichstatementscanbeinsertedatposition1withoutcausingthecodetofailcompilation?

publicclassQ6db8{

inta;

intb=0;

staticintc;

publicvoidm(){

intd;

inte=0;

//Position1

}

}

1)a++;

2)b++;

3)c++;

4)d++;

5)e++;

Q10

Whichstatementsaretrueconcerningtheeffectofthe>>and>>>operators?

1)Fornon-negativevaluesoftheleftoperand,the>>and>>>operatorswillhavethesameeffect.

2)Theresultof(-1>>1)is0.

3)Theresultof(-1>>>1)is-1.

4)Thevaluereturnedby>>>willneverbenegativeaslongasthevalueoftherightoperandisequaltoorgreaterthan1.

5)Whenusingthe>>operator,theleftmostbitofthebitrepresentationoftheresultingvaluewillalwaysbethesamebitvalueastheleftmostbitofthebitrepresentationoftheleftoperand.

Q11

Whatiswrongwiththefollowingcode?

classMyExceptionextendsException{}

publicclassQb4ab{

publicvoidfoo(){

try{

bar();

}finally{

baz();

}catch(MyExceptione){}

}

publicvoidbar()throwsMyException{

thrownewMyException();

}

publicvoidbaz()throwsRuntimeException{

thrownewRuntimeException();

}

}

1)Sincethemethodfoo()doesnotcatchtheexceptiongeneratedbythemethodbaz(),itmustdeclaretheRuntimeExceptioninitsthrowsclause.

2)Atryblockcannotbefollowedbybothacatchandafinallyblock.

3)Anemptycatchblockisnotallowed.

4)Acatchblockcannotfollowafinallyblock.

5)Afinallyblockmustalwaysfollowoneormorecatchblocks.

Q12

Whatwillbewrittentothestandardoutputwhenthefollowingprogramisrun?

publicclassQd803{

publicstaticvoidmain(Stringargs[]){

Stringword="restructure";

System.out.println(word.substring(2,3));

}

}

1)est

2)es

3)str

4)st

5)s

Q13

GiventhatastaticmethoddoIt()inaclassWorkrepresentsworktobedone,whatblockofcodewillsucceedinstartinganewthreadthatwilldothework?

CODEBLOCKA:

Runnabler=newRunnable(){

publicvoidrun(){

Work.doIt();

}

};

Threadt=newThread(r);

t.start();

CODEBLOCKB:

Threadt=newThread(){

publicvoidstart(){

Work.doIt();

}

};

t.start();

CODEBLOCKC:

Runnabler=newRunnable(){

publicvoidrun(){

Work.doIt();

}

};

r.start();

CODEBLOCKD:

Threadt=newThread(newWork());

t.start();

CODEBLOCKE:

Runnablet=newRunnable(){

publicvoidrun(){

Work.doIt();

}

};

t.run();

1)CodeblockA.

2)CodeblockB.

3)CodeblockC.

4)CodeblockD.

5)CodeblockE.

Q14

WritealineofcodethatdeclaresavariablenamedlayoutoftypeLayoutManagerandinitializesitwithanewobject,whichwhenusedwithacontainercanlayoutcomponentsinarectangulargridofequal-sizedrectangles,3componentswideand2componentshigh.

Q15

publicclassQ275d{

staticinta;

intb;

publicQ275d(){

intc;

c=a;

a++;

b+=c;

}

publicstaticvoidmain(Stringargs[]){

newQ275d();

}

}

1)Thecodewillfailtocompile,sincetheconstructoristryingtoaccessstaticmembers.

2)Thecodewillfailtocompile,sincetheconstructoristryingtousestaticmembervariableabeforeithasbeeninitialized.

3)Thecodewillfailtocompile,sincetheconstructoristryingtousemembervariablebbeforeithasbeeninitialized.

4)Thecodewillfailtocompile,sincetheconstructoristryingtouselocalvariablecbeforeithasbeeninitialized.

5)Thecodewillcompileandrunwithoutanyproblems.

Q16

Whatwillbewrittentothestandardoutputwhenthefollowingprogramisrun?

publicclassQ63e3{

publicstaticvoidmain(Stringargs[]){

System.out.println(9^2);

}

}

1)81

2)7

3)11

4)0

5)false

Q17

Whichstatementsaretrueconcerningthedefaultlayoutmanagerforcontainersinthejava.awtpackage?

1)ObjectsinstantiatedfromPaneldonothaveadefaultlayoutmanager.

2)ObjectsinstantiatedfromPanelhaveFlowLayoutasdefaultlayoutmanager.

3)ObjectsinstantiatedfromApplethaveBorderLayoutasdefaultlayoutmanager.

4)ObjectsinstantiatedfromDialoghaveBorderLayoutasdefaultlayoutmanager.

5)ObjectsinstantiatedfromWindowhavethesamedefaultlayoutmanagerasinstancesofApplet.

Q18

Whichdeclarationswillallowaclasstobestartedasastandaloneprogram?

1)publicvoidmain(Stringargs[])

2)publicvoidstaticmain(Stringargs[])

3)publicstaticmain(String[]argv)

4)finalpublicstaticvoidmain(String[]array)

5)publicstaticvoidmain(Stringargs[])

Q19

Underwhichcircumstanceswillathreadstop?

1)ThemethodwaitforId()inclassMediaTrackeriscalled.

2)Therun()methodthatthethreadisexecutingends.

3)Thecalltothestart()methodoftheThreadobjectreturns.

4)Thesuspend()methodiscalledontheThreadobject.

5)Thewait()methodiscalledontheThreadobject.

Q20

Whencreatingaclassthatassociatesasetofkeyswithasetofvalues,whichoftheseinterfacesismostapplicable?

1)Collection

2)Set

3)SortedSet

4)Map

Q21

WhatdoesthevaluereturnedbythemethodgetID()foundinclassjava.awt.AWTEventuniquelyidentify?

1)Theparticulareventinstance.

2)Thesourceoftheevent.

3)Thesetofeventsthatweretriggeredbythesameaction.

4)Thetypeofevent.

5)Thetypeofcomponentfromwhichtheeventoriginated.

Q22

Whatwillbewrittentothestandardoutputwhenthefollowingprogramisrun?

classBase{

inti;

Base(){

add(1);

}

voidadd(intv){

i+=v;

}

voidprint(){

System.out.println(i);

}

}

classExtensionextendsBase{

Extension(){

add(2);

}

voidadd(intv){

i+=v*2;

}

}

publicclassQd073{

publicstaticvoidmain(Stringargs[]){

bogo(newExtension());

}

staticvoidbogo(Baseb){

b.add(8);

b.print();

}

}

1)9

2)18

3)20

4)21

5)22

Q23

Whichlinesofcodearevaliddeclarationsofanativemethodwhenoccurringwithinthedeclarationofthefollowingclass?

publicclassQf575{

//insertdeclarationofanativemethodhere

}

1)nativepublicvoidsetTemperature(intkelvin);

2)privatenativevoidsetTemperature(intkelvin);

3)protectedintnativegetTemperature();

4)publicabstractnativevoidsetTemperature(intkelvin);

5)nativeintsetTemperature(intkelvin){}

Q24

HowdoestheweightypropertyoftheGridBagConstraintsobjectsusedingridbaglayoutaffectthelayoutofthecomponents?

1)Itaffectswhichgridcellthecomponentsendupin.

2)Itaffectshowtheextraverticalspaceisdistributed.

3)Itaffectsthealignmentofeachcomponent.

4)Itaffectswhetherthecomponentscompletelyfilltheirallotteddisplayareavertically.

Q25

Whichstatementscanbeinsertedattheindicatedpositioninthefollowingcodetomaketheprogramwrite1onthestandardoutputwhenrun?

publicclassQ4a39{

inta=1;

intb=1;

intc=1;

classInner{

inta=2;

intget(){

intc=3;

//insertstatementhere

returnc;

}

}

Q4a39(){

Inneri=newInner();

System.out.println(i.get());

}

publicstaticvoidmain(Stringargs[]){

newQ4a39();

}

}

1)c=b;

2)c=this.a;

3)c=this.b;

4)c=Q4a39.this.a;

5)c=c;

Q26

Whichistheearliestlineinthefollowingcodeafterwhichtheobjectcreatedonthelinemarked(0)willbeacandidateforbeinggarbagecollected,assumingnocompileroptimizationsaredone?

publicclassQ76a9{

staticStringf(){

Stringa="hello";

Stringb="bye";//(0)

Stringc=b+"!";//(1)

Stringd=b;

b=a;//(2)

d=a;//(3)

returnc;//(4)

}

publicstaticvoidmain(Stringargs[]){

Stringmsg=f();

System.out.println(msg);//(5)

}

}

1)Thelinemarked(1).

2)Thelinemarked(2).

3)Thelinemarked(3).

4)Thelinemarked(4).

5)Thelinemarked(5).

Q27

WhichmethodsfromtheStringandStringBufferclassesmodifytheobjectonwhichtheyarecalled?

1)ThecharAt()methodoftheStringclass.

2)ThetoUpperCase()methodoftheStringclass.

3)Thereplace()methodoftheStringclass.

4)Thereverse()methodoftheStringBufferclass.

5)Thelength()methodoftheStringBufferclass.

Q28

Whichstatements,wheninsertedattheindicatedpositioninthefollowingcode,willcausearuntimeexceptionwhenattemptingtoruntheprogram?

classA{}

classBextendsA{}

classCextendsA{}

publicclassQ3ae4{

publicstaticvoidmain(Stringargs[]){

Ax=newA();

By=newB();

Cz=newC();

//insertstatementhere

}

}

1)x=y;

2)z=x;

3)y=(B)x;

4)z=(C)y;

5)y=(A)y;

Q29

WhichofthesearekeywordsinJava?

1)default

2)NULL

3)String

4)throws

5)long

Q30

Itisdesirablethatacertainmethodwithinacertainclasscanonlybeaccessedbyclassesthataredefinedwithinthesamepackageastheclassofthemethod.Howcansuchrestrictionsbeenforced?

1)Markthemethodwiththekeywordpublic.

2)Markthemethodwiththekeywordprotected.

3)Markthemethodwiththekeywordprivate.

4)Markthemethodwiththekeywordpackage.

5)Donotmarkthemethodwithanyaccessibilitymodifiers.

Q31

Whichcodefragmentswillsucceedininitializingatwo-dimensionalarraynamedtabwithasizethatwillcausetheexpressiontab[3][2]toaccessavalidelement?

CODEFRAGMENTA:

int[][]tab={

{0,0,0},

{0,0,0}

};

CODEFRAGMENTB:

inttab[][]=newint[4][];

for(inti=0;i

CODEFRAGMENTC:

inttab[][]={

0,0,0,0,

0,0,0,0,

0,0,0,0,

0,0,0,0

};

CODEFRAGMENTD:

inttab[3][2];

CODEFRAGMENTE:

int[]tab[]={{0,0,0},{0,0,0},{0,0,0},{0,0,0}};

1)CodefragmentA.

2)CodefragmentB.

3)CodefragmentC.

4)CodefragmentD.

5)CodefragmentE.

Q32

Whatwillbetheresultofattemptingtorunthefollowingprogram?

publicclassQaa75{

publicstaticvoidmain(Stringargs[]){

String[][][]arr={

{{},null},

{{"1","2"},{"1",null,"3"}},

{},

{{"1",null}}

};

System.out.println(arr.length+arr[1][2].length);

}

}

1)TheprogramwillterminatewithanArrayIndexOutOfBoundsException.

2)TheprogramwillterminatewithaNullPointerException.

3)4willbewrittentostandardoutput.

4)6willbewrittentostandardoutput.

5)7willbewrittentostandardoutput.

Q33

Whichexpressionswillevaluatetotrueifprecededbythefollowingcode?

Stringa="hello";

Stringb=newString(a);

Stringc=a;

char[]d={'h','e','l','l','o'};

1)(a=="Hello")

2)(a==b)

3)(a==c)

4)a.equals(b)

5)a.equals(d)

Q34

Whichstatementsconcerningthefollowingcodearetrue?

classA{

publicA(){}

publicA(inti){this();}

}

classBextendsA{

publicbooleanB(Stringmsg){returnfalse;}

}

classCextendsB{

privateC(){super();}

publicC(Stringmsg){this();}

publicC(inti){}

}

1)Thecodewillfailtocompile.

2)TheconstructorinAthattakesanintasanargumentwillneverbecalledasaresultofconstructinganobjectofclassBorC.

3)ClassChasthreeconstructors.

4)ObjectsofclassBcannotbeconstructed.

5)AtmostoneoftheconstructorsofeachclassiscalledasaresultofconstructinganobjectofclassC.

Q35

Giventwocollectionobjectsreferencedbycol1andcol2,whichofthesestatementsaretrue?

1)Theoperationcol1.retainAll(col2)willnotmodifythecol1object.

2)Theoperationcol1.removeAll(col2)willnotmodifythecol2object.

3)Theoperationcol1.addAll(col2)willreturnanewcollectionobject,

containingelementsfrombothcol1andcol2.

4)Theoperationcol1.containsAll(Col2)willnotmodifythecol1object.

Q36

Whichstatementsconcerningtherelationshipsbetweenthefollowingclassesaretrue?

classFoo{

intnum;

Bazcomp=newBaz();

}

classBar{

booleanflag;

}

classBazextendsFoo{

Barthing=newBar();

doublelimit;

}

1)ABarisaBaz.

2)AFoohasaBar.

3)ABazisaFoo.

4)AFooisaBaz.

5)ABazhasaBar.

Q37

Whichstatementsconcerningthevalueofamembervariablearetrue,whennoexplicitassignmentshavebeenmade?

1)Thevalueofanintisundetermined.

2)Thevalueofallnumerictypesiszero.

3)Thecompilermayissueanerrorifthevariableisusedbeforeitisinitialized.

4)ThevalueofaStringvariableis""(emptystring).

5)Thevalueofallobjectvariablesisnull.

Q38

Whichstatementsdescribeguaranteedbehaviorofthegarbagecollectionandfinalizationmechanisms?

1)Objectsaredeletedwhentheycannolongerbeaccessedthroughanyreference.

2)Thefinalize()methodwilleventuallybecalledoneveryobject.

3)Thefinalize()methodwillneverbecalledmorethanonceonanobject.

4)Anobjectwillnotbegarbagecollectedaslongasitispossibleforanactivepartoftheprogramtoaccessitthroughareference.

5)Thegarbagecollectorwilluseamarkandsweepalgorithm.

Q39

Whichcodefragmentswillsucceedinprintingthelastargumentgivenonthecommandlinetothestandardoutput,andexitgracefullywithnooutputifnoargumentsaregiven?

CODEFRAGMENTA:

publicstaticvoidmain(Stringargs[]){

if(args.length!=0)

System.out.println(args[args.length-1]);

}

CODEFRAGMENTB:

publicstaticvoidmain(Stringargs[]){

try{System.out.println(args[args.length]);}

catch(ArrayIndexOutOfBoundsExceptione){}

}

CODEFRAGMENTC:

publicstaticvoidmain(Stringargs[]){

intix=args.length;

Stringlast=args[ix];

if(ix!=0)System.out.println(last);

}

CODEFRAGMENTD:

publicstaticvoidmain(Stringargs[]){

intix=args.length-1;

if(ix>0)System.out.println(args[ix]);

}

CODEFRAGMENTE:

publicstaticvoidmain(Stringargs[]){

try{System.out.println(args[args.length-1]);}

catch(NullPointerExceptione){}

}

1)CodefragmentA.

2)CodefragmentB.

3)CodefragmentC.

4)CodefragmentD.

5)CodefragmentE.

Q40

Whichofthesestatementsconcerningthecollectioninterfacesaretrue?

1)SetextendsCollection.

2)AllmethodsdefinedinSetarealsodefinedinCollection.

3)ListextendsCollection.

4)AllmethodsdefinedinListarealsodefinedinCollection.

5)MapextendsCollection.

Q41

Whatisthenameofthemethodthatthreadscanusetopausetheirexecutionuntilsignalledtocontinuebyanotherthread?

Fillinthenameofthemethod(donotincludeaparameterlist).

Q42

Giventhefollowingclassdefinitions,whichexpressionidentifieswhethertheobjectreferredtobyobjwascreatedbyinstantiatingclassBratherthanclassesA,CandD?

classA{}

classBextendsA{}

classCextendsB{}

classDextendsA{}

1)objinstanceofB

2)objinstanceofA&&!(objinstanceofC)

3)objinstanceofB&&!(objinstanceofC)

4)objinstanceofC||objinstanceofD

5)(objinstanceofA)&&!(objinstanceofC)&&!(objinstanceofD)

Q43

Whatwillbewrittentothestandardoutputwhenthefollowingprogramisrun?

publicclassQ8499{

publicstaticvoidmain(Stringargs[]){

doubled=-2.9;

inti=(int)d;

i*=(int)Math.ceil(d);

i*=(int)Math.abs(d);

System.out.println(i);

}

}

1)12

2)18

3)8

4)12

5)27

Q44

Whatwillbewrittentothestandardoutputwhenthefollowingprogramisrun?

publicclassQcb90{

inta;

intb;

publicvoidf(){

a=0;

b=0;

int[]c={0};

g(b,c);

System.out.println(a+""+b+""+c[0]+"");

}

publicvoidg(intb,int[]c){

a=1;

b=1;

c[0]=1;

}

publicstaticvoidmain(Stringargs[]){

Qcb90obj=newQcb90();

obj.f();

}

}

1)000

2)001

3)010

4)100

5)101

Q45

Whichstatementsconcerningtheeffectofthestatementgfx.drawRect(5,5,10,10)aretrue,giventhatgfxisareferencetoavalidGraphicsobject?

1)Therectangledrawnwillhaveatotalwidthof5pixels.

2)Therectangledrawnwillhaveatotalheightof6pixels.

3)Therectangledrawnwillhaveatotalwidthof10pixels.

4)Therectangledrawnwillhaveatotalheightof11pixels.

Q46

Giventhefollowingcode,whichcodefragments,wheninsertedattheindicatedlocation,willsucceedinmakingtheprogramdisplayabuttonspanningthewholewindowarea?

importjava.awt.*;

publicclassQ1e65{

publicstaticvoidmain(Stringargs[]){

Windowwin=newFrame();

Buttonbut=newButton("button");

//insertcodefragmenthere

win.setSize(200,200);

win.setVisible(true);

}

}

1)win.setLayout(newBorderLayout());win.add(but);

2)win.setLayout(newGridLayout(1,1));win.add(but);

3)win.setLayout(newBorderLayout());win.add(but,BorderLayout.CENTER);

4)win.add(but);

5)win.setLayout(newFlowLayout());win.add(but);

Q47

Whichmethodimplementationswillwritethegivenstringtoafilenamed"file",usingUTF8encoding?

IMPLEMENTATIONA:

publicvoidwrite(Stringmsg)throwsIOException{

FileWriterfw=newFileWriter(newFile("file"));

fw.write(msg);

fw.close();

}

IMPLEMENTATIONB:

publicvoidwrite(Stringmsg)throwsIOException{

OutputStreamWriterosw=

newOutputStreamWriter(newFileOutputStream("file"),"UTF8");

osw.write(msg);

osw.close();

}

IMPLEMENTATIONC:

publicvoidwrite(Stringmsg)throwsIOException{

FileWriterfw=newFileWriter(newFile("file"));

fw.setEncoding("UTF8");

fw.write(msg);

fw.close();

}

IMPLEMENTATIOND:

publicvoidwrite(Stringmsg)throwsIOException{

FilterWriterfw=FilterWriter(newFileWriter("file"),"UTF8");

fw.write(msg);

fw.close();

}

IMPLEMENTATIONE:

publicvoidwrite(Stringmsg)throwsIOException{

OutputStreamWriterosw=newOutputStreamWriter(

newOutputStream(newFile("file")),"UTF8"

);

osw.write(msg);

osw.close();

}

1)ImplementationA.

2)ImplementationB.

3)ImplementationC.

4)ImplementationD.

5)ImplementationE.

Q48

Whicharevalididentifiers?

1)_class

2)$value$

3)zer@

4)￥ngstr

5)2muchuq

Q49

Whatwillbetheresultofattemptingtocompileandrunthefollowingprogram?

publicclassQ28fd{

publicstaticvoidmain(Stringargs[]){

intcounter=0;

l1:

for(inti=10;i<0;i--){

l2:

intj=0;

while(j<10){

if(j>i)breakl2;

if(i==j){

counter++;

continuel1;

}

}

counter--;

}

System.out.println(counter);

}

}

1)Theprogramwillfailtocompile.

2)Theprogramwillnotterminatenormally.

3)Theprogramwillwrite10tothestandardoutput.

4)Theprogramwillwrite0tothestandardoutput.

5)Theprogramwillwrite9tothestandardoutput.

Q50

Giventhefollowinginterfacedefinition,whichdefinitionsarevalid?

interfaceI{

voidsetValue(intval);

intgetValue();

}

DEFINITIONA:

(a)classAextendsI{

intvalue;

voidsetValue(intval){value=val;}

intgetValue(){returnvalue;}

}

DEFINITIONB:

(b)interfaceBextendsI{

voidincrement();

}

DEFINITIONC:

(c)abstractclassCimplementsI{

intgetValue(){return0;}

abstractvoidincrement();

}

DEFINITIOND:

(d)interfaceDimplementsI{

voidincrement();

}

DEFINITIONE:

(e)classEimplementsI{

intvalue;

publicvoidsetValue(intval){value=val;}

}

1)DefinitionA.

2)DefinitionB.

3)DefinitionC.

4)DefinitionD.

5)DefinitionE.

Q51

Whichstatementsconcerningthemethodsnotify()andnotifyAll()aretrue?

1)InstancesofclassThreadhaveamethodcallednotify().

2)Acalltothemethodnotify()willwakethethreadthatcurrentlyownsthemonitoroftheobject.

3)Themethodnotify()issynchronized.

4)ThemethodnotifyAll()isdefinedinclassThread.

5)Whenthereismorethanonethreadwaitingtoobtainthemonitorofanobject,thereisnowaytobesurewhichthreadwillbenotifiedbythenotify()method.

Q52

Whichstatementsconcerningthecorrelationbetweentheinnerandouterinstancesofnon-staticinnerclassesaretrue?

1)Membervariablesoftheouterinstancearealwaysaccessibletoinnerinstances,regardlessoftheiraccessibilitymodifiers.

2)Membervariablesoftheouterinstancecanneverbereferredtousingonlythevariablenamewithintheinnerinstance.

3)Morethanoneinnerinstancecanbeassociatedwiththesameouterinstance.

4)Allvariablesfromtheouterinstancethatshouldbeaccessibleintheinnerinstancemustbedeclaredfinal.

5)Aclassthatisdeclaredfinalcannothaveanyinnerclasses.

Q53

Whatwillbetheresultofattemptingtocompileandrunthefollowingcode?

publicclassQ6b0c{

publicstaticvoidmain(Stringargs[]){

inti=4;

floatf=4.3;

doubled=1.8;

intc=0;

if(i==f)c++;

if(((int)(f+d))==((int)f+(int)d))c+=2;

System.out.println(c);

}

}

1)Thecodewillfailtocompile.

2)0willbewrittentothestandardoutput.

3)1willbewrittentothestandardoutput.

4)2willbewrittentothestandardoutput.

5)3willbewrittentothestandardoutput.

Q54

Whichoperatorswillalwaysevaluatealltheoperands?

1)||

2)+

3)&&

4)?:

5)%

Q55

Whichstatementsconcerningtheswitchconstructaretrue?

1)Allswitchstatementsmusthaveadefaultlabel.

2)Theremustbeexactlyonelabelforeachcodesegmentinaswitchstatement.

3)Thekeywordcontinuecanneveroccurwithinthebodyofaswitchstatement.

4)Nocaselabelmayfollowadefaultlabelwithinasingleswitchstatement.

5)Acharacterliteralcanbeusedasavalueforacaselabel.

Q56

Whichmodifiersandreturntypeswouldbevalidinthedeclarationofaworkingmain()methodforaJavastandaloneapplication?

1)private

2)final

3)static

4)int

5)abstract

Q57

Whatwillbetheappearanceofanappletwiththefollowinginit()method?

publicvoidinit(){

add(newButton("hello"));

}

1)Nothingappearsintheapplet.

2)Abuttonwillcoverthewholeareaoftheapplet.

3)Abuttonwillappearinthetopleftcorneroftheapplet.

4)Abuttonwillappear,centeredinthetopregionoftheapplet.

5)Abuttonwillappearinthecenteroftheapplet.

Q58

WhichstatementsconcerningtheeventmodeloftheAWTaretrue?

1)Atmostonelistenerofeachtypecanberegisteredwithacomponent.

2)MousemotionlistenerscanberegisteredonaListinstance.

3)ThereexistsaclassnamedContainerEventinpackagejava.awt.event.

4)ThereexistsaclassnamedMouseMotionEventinpackagejava.awt.event.

5)ThereexistsaclassnamedActionAdapterinpackagejava.awt.event.

Q59

Whichstatementsaretrue,giventhecodenewFileOutputStream("data",true)forcreatinganobjectofclassFileOutputStream?

1)FileOutputStreamhasnoconstructorsmatchingthegivenarguments.

2)AnIOExeceptionwillbethrownifafilenamed"data"alreadyexists.

3)AnIOExeceptionwillbethrownifafilenamed"data"doesnotalreadyexist.

4)Ifafilenamed"data"exists,itscontentswillberesetandoverwritten.

5)Ifafilenamed"data"exists,outputwillbeappendedtoitscurrentcontents.

Q60

Giventhefollowingcode,writealineofcodethat,wheninsertedattheindicatedlocation,willmaketheoverridingmethodinExtensioninvoketheoverriddenmethodinclassBaseonthecurrentobject.

classBase{

publicvoidprint(){

System.out.println("base");

}

}

classExtentionextendsBase{

publicvoidprint(){

System.out.println("extension");

//insertlineofimplementationhere

}

}

publicclassQ294d{

publicstaticvoidmain(Stringargs[]){

Extentionext=newExtention();

ext.print();

}

}

Fillinasinglelineofimplementation.

Q61

GiventhatfileisareferencetoaFileobjectthatrepresentsadirectory,whichcodefragmentswillsucceedinobtainingalistoftheentriesinthedirectory?

1)Vectorfilelist=((Directory)file).getList();

2)String[]filelist=file.directory();

3)Enumerationfilelist=file.contents();

4)String[]filelist=file.list();

5)Vectorfilelist=(newDirectory(file)).files();

Q62

Whatwillbewrittentothestandardoutputwhenthefollowingprogramisrun?