计算机考试之java面试题库

JAVA基础部分面试题库

第一部分：选择题

1)哪个不是面向对象的特征()

a)封装性b)继承性c)多态性d)健壮性

2)编译JAVA文件的命令是()o

a)Javab)Javacc)Javadbd)Javaw

3)JAVA源文件的扩展名是()o

a)Classb)exec)javad)dll

4)JAVA内部使用的编码格式是()。

a)UTF-8b)ASCIIc)UNICODEd)ISO8859-1

5)下列变量名称不合法的是()

a)Indexb)$bc3&c)_cccded)34#bc5

6)下边对基本数据类型的说明正确的是()

a)Int可以自动转换为BYTE类型

b)DOUBLE类型的数据占用2个字节

c)JAVA中一共有4类8种基本数据类型

d)JAVA中一共有3类8种基本数据类型

7)下列不是JAVA关键字的是()

a)gotob)ifc)countd)private

8)下列变量声明中正确的是()

a)Floatf=3.13b)Booleanb=0

c)Intnumber=5d)IntxBytea=x

9)publicvoidgo(){

Stringo二心；

z:

for(intx=0;x<3;x++){

for(inty=0;y<2;y++){

if(x==l)break;

if(x==2&&y==l)breakz;

o=o+x+y;

)

)

System.out.println(o);

)

程序的执行结果是()

a)00

b)0001

c)000120

d)00012021

e)Compilationfails.

f)Anexceptionisthrownatruntime

10)classPayload{

privateintweight;

publicPayload(intw){weight=w;}

publicvoidsetWeight(intw){weight=w;}

publicStringtoStringO{returnInteger.toString(weight);}

)

publicclassTestPayload{

staticvoidchangePayload(Payloadp){/*insertcode*/}

publicstaticvoidmain(String[]args){

Payloadp=newPayload(200);

p.setWeight(1024);

changePayload(p);

System.out.println(npis”+p);

}

)

Insertcode处写入哪句话，可以使程序的输出结果是420()

a)p.setWeight(420);

b)p.changePay!oad(420);

c)p=newPayload(420);

d)Payload.setWeight(420);

e)p=Payload.setWeight(420);

11)voidwaitForSignal(){

Objectobj=newObjectQ;

synchronized(Thread.currentThreadO){

obj.wait();

obj.notify();

)

}这个程序片段的运行结果是什么()

a)ThiscodecanthrowanInterruptedException.

b)ThiscodecanthrowanIllegalMonitorStateException.

c)ThiscodecanthrowaTimeoutExceptionaftertenminutes.

d)Reversingtheorderofobj.wait()andobj.notifyOmightcausethismethodtocomplete

normally.

12)publicclassThreads2implementsRunnable{

publicvoidrun(){

System.out.println(nrun.H);

thrownewRuntimeException('^Problem^^);

)

publicstaticvoidmain(String[]args){

Threadt=newThread(newThreads2());

t.start();

System.out.println(nEndofmethod.");

运行结果是什么，请选择2个()

a)java.lang.RuntimeException:Problem

b)run.java.lang.RuntimeException:Problem

c)Endofmethod.java.lang.RuntimeException:Problem

d)Endofmethod,run.java.Iang.RuntimeException:Problem

e)run.java.lang.RuntimeException:ProblemEndofmethod.

13)下边哪2句话的描述是正确的()

a)Itispossibleformorethantwothreadstodeadlockatonce

b)TheJVMimplementationguaranteesthatmultiplethreadscannotenterintoadeadlocked

state.

c)Deadlockedthreadsreleaseoncetheirsleep()method'ssleepdurationhasexpired.

d)Deadlockingcanoccuronlywhenthewait(),notify(),andnotifyAll()methodsareused

incorrectly.

e)Itispossibleforasingle-threadedapplicationtodeadlockifsynchronizedblocksareused

incorrectly.

f)fapieceofcodeiscapableofdeadlocking,youcannoteliminatethepossibilityof

deadlockingbyinsertinginvocationsofThread.yield().

14)publicclassThreads!implementsRunnable{

publicvoidrun(){

System.out.println("run.n);

thrownewRuntimeException(nProblemn);

}

publicstaticvoidmain(String[]args){

Threadt=newThread(newThreads2());

t.start();

System.out.println(nEndofmethod.");

)

}程序运行结果是，选择2个()

a)java.lang.RuntimeException:Problem

b)run.java.lang.RuntimeException:ProblemEndofmethod

c)Endofmethod.java.lang.RuntimeException:Problem

d)Endofmethod,run.java.lang.RuntimeException:Problem

15)voidwaitForSignal(){

Objectobj=newObject();

synchronized(Thread.currentThread()){

obj.wait();

obj.notifyO;

)

}下列那句描述是正确的()

a)ThiscodecanthrowanInterruptedException.

b)ThiscodecanthrowanIllegalMonitorStateException.

c)ThiscodecanthrowaTimeoutExceptionaftertenminutes.

d)ThiscodedoesNOTcompileunlessnobj.wait()nisreplacedwith"((Thread)obj).wait()n.

16)11.classPingPong2{

synchronizedvoidhit(longn){

for(inti=1;i<3;i++)

System.out.print(n++i+””)；

)

}

publicclassTesterimplementsRunnable{

staticPingPong2pp2=newPingPong2();

publicstaticvoidmain(String[]args){

newThread(newTester()).start();

newThread(newTester()).start();

.publicvoidrun(){pp2.hit(Thread.currentThread().getId());}

}运行结果是()

a)Theoutputcouldbe5-16-16-25-2

b)Theoutputcouldbe6-16-25-15-2

c)Theoutputcouldbe6-15-26-25-1

d)Theoutputcouldbe6-16-25-17-1

17)1.publicclassThreads4{

publicstaticvoidmain(String[]args){

newThreads4().go();

)

publicvoidgo(){

Runnabler=newRunnable(){

publicvoidrun(){System.out.print(”foo")；

)

);

Threadt=newThread(r);

t.start();

t.startQ;

｝运行结果是()

a)Compilationfails.

b)Anexceptionisthrownatruntime.

c)Thecodeexecutesnormallyandprints"foon.

d)Thecodeexecutesnormally,butnothingisprinted.

18)11.publicclassBarn{

publicstaticvoidmain(String[]args){

newBam().go(”hi”，1);

newBarn().go(”hi”，“world”，2);

)

publicvoidgo(String...y,intx){

System.out.print(y[y.length-1]+”

)

}运行结果是()

a)hihi

b)hiworld

c)Compilationfails

d)Anexceptionisthrownatruntime.

19)10.classNav{

.publicenumDirection{NORTH,SOUTH,EAST,WEST}

)

publicclassSprite{

//insertcodehere

}哪句代码放到14行，程序可以正常编译()

a)Directiond=NORTH;

b)Nav.Directiond=NORTH;

c)Directiond=Direction.NORTH;

d)Nav.Directiond=Nav.Direction.NORTH;

20)11.publicclassRainbow{

publicenumMyColor{

RED(OxffOOOO),GREEN(OxOOffOO),BLUE(OxOOOOff);

privatefinalintrgb;

MyColor(intrgb){this.rgb=rgb;}

publicintgetRGB(){returnrgb;}

);

publicstaticvoidmain(String[]args){

//insertcodehere

)

}哪句代码放到19行，程序可以正常编译()

a)MyColorskyColor=BLUE;

b)MyColortreeColor=MyColor.GREEN;

c)Compilationfailsduetoothererror(s)inthecode.

d)MyColorpurple=MyColor.BLUE+MyColor.RED;

21)5.classAtom{

Atom(){System.out.print(natom”)；}

)

classRockextendsAtom{

Rock(Stringtype){System.out.print(type);}

}■■

publicclassMountainextendsRock{

Mountain(){

super(Mgranite")；

newRock("granite");

}

publicstaticvoidmain(String[]a){newMountain();}

}运行结果是()

a)Compilationfails

b)atomgranitegranite

c)Anexceptionisthrownatruntime.

d)atomgraniteatomgranite

22)1.interfaceTestA{StringtoStringO;}

publicclassTest{

publicstaticvoidmain(String[]args){

4System.out.println(newTestA(){

publicStringtoStringO{return"test";}

));

｝运行结果是（）

a)test

b)null

c)Anexceptionisthrownatruntime.

d)Compilationfailsbecauseofanerrorinline1.

23)11.publicstaticvoidparse(Stringstr){

try{

floatf=Float.parseFloat(str);

}catch(NumberFormatExceptionnfe){

f=0;}finally{

17.System.out.println(f)；

publicstaticvoidmain(String[]args){

parseC4nvalid'1);

}运行结果是()

a)0.0

b)Compilationfails.

c)AParseExceptionisthrownbytheparsemethodatruntime

d)ANumberFormatExceptionisthrownbytheparsemethodatruntime

24)1.publicclassBlip{

protectedintblipvert(intx){return0;}

)

classVertextendsBlip{

//insertcodehere

}下列哪5个方法放到代码第五行，可以让程序编译正确，选择5个()

a)publicintblipvert(intx){return0;}

b)privateintblipvert(intx){return0;}

c)privateintblipvert(longx){return0;}

d)protectedlongblipvert(intx){return0;}

e)protectedintblipvert(longx){return0;}

f)protectedlongblipvert(longx){return0;}

g)protectedlongblipvert(intx,inty){return0;}

25)1.classSuper{

privateinta;

protectedSuper(inta){this.a=a;}

}...

classSubextendsSuper{

publicSub(inta){super(a);}

publicSub(){this.a=5;}

}下列哪2条语句是正确的()

a)Changeline2to:publicinta;

b)Changeline2to:protectedinta;

c)Changeline13to:publicSub(){this(5);}

d)Changeline13to:publicSub(){super(5);}

e)Changeline13to:publicSub(){super(a);}

26)packagetest;

classTarget{

publicStringname="hello”；

}如果可以直接修改和访问name这个变量，下列哪句话是正确的()

a)anyclass

b)onlytheTargetclass

c)anyclassinthetestpackage

d)anyclassthatextendsTarget

27)11.abstractclassVehicle{publicintspeed(){return0;}

classCarextendsVehicle{publicintspeed(){return60;}

classRaceCarextendsCar{publicintspeed(){return150;}...

RaceCarracer=newRaceCar();

Carcar=newRaceCar();

Vehiclevehicle=newRaceCarQ;

System.out.println(racer.speed()+"+car.speed()

+*”+vehicle.speed。);运行结果是()

a)0,0,0

b)150,60,0

c)Compilationfails

d)150,150,150

e)Anexceptionisthrownatruntime

28)5.classBuilding{}

publicclassBarnextendsBuilding{

publicstaticvoidmain(String[]args){

Buildingbuild1=newBuildingO;

Barnbaml=newBarn();

Barnbam2=(Bam)build1;

Objectobjl=(Object)build1;

Stringstrl=(String)build1;

Buildingbuild2=(Building)baml;

}15.}运行结果是()

a)Ifline10isremoved,thecompilationsucceeds.

b)Ifline11isremoved,thecompilationsucceeds

c)Ifline12isremoved,thecompilationsucceeds.

d)Ifline13isremoved,thecompilationsucceeds.

e)Morethanonelinemustberemovedforcompilationtosucceed.

29)29.Given:

classMoney{

privateStringcountry="Canada*1;

publicStringgetC(){returncountry;}

)

classYenextendsMoney{

publicStringgetC(){returnsuper.country;}

),

publicclassEuroextendsMoney{

publicStringgetC(intx){returnsuper.getC();}

publicstaticvoidmain(String[]args){

System.out.print(newYen().getC()+””+newEuro().getC());

}33.}运行结果是()

a)Canada

b)nullCanada

c)Canadanull

d)Compilationfailsduetoanerroronline26

e)Compilationfailsduetoanerroronline29

30)13.importjava.io.*;

classFoodimplementsSerializable{intgood=3;}

classFruitextendsFood{intjuice=5;)

publicclassBananaextendsFruit{

intyellow=4;

publicstaticvoidmain(String[]args){

Bananab=newBanana();Bananab2=newBanana();

b.serializeBanana(b);//assumecorrectserialization

b2=b.deserializeBanana();//assumecorrect

System.out.printlnC^restore"+b2.yellow+b2.juice+b2.good);

)

//moreBananamethodsgohere

}运行结果是()

a)restore400

b)restore403

c)restore453

d)Compilationfails.

e)Anexceptionisthrownatruntime.

31)11.doubleinput=314159.26;

NumberFormatnf=NumberFormat.getlnstance(Locale.ITALIAN);

Stringb;

//insertcodehere

下列哪条语句可以设置变量b的值为314.159,26()

a).b=nf.parse(input);

b)b=nf.format(input);

c)b=nf.equals(input);

d)b=nf.parseObject(input);

32)1.publicclassTestStringl{

publicstaticvoidmain(String[]args){

Stringstr="420”；

str+=42;

System.out.print(str);

}7.}输出结果是()

a)42b)420c)462d)42042

33)22.StringBuildersbl=newStringBuilder(H123n);

Stringsi=123”；

//insertcodehere

System.out.println(sb1+””+si);

下列哪句代码放到程序的第24行,可以输出"23abcl23abc”()

a)sbl.append(MabcH);sl.append(nabc");

b)sbl.append(HabcH);s1.concat("abc");

c)sbl.concat(nabcn);sl.append("abc");

d)sbl.concat(nabcn);sl.concat(nabcn);

e)sbl.append(uabcn);si=sl.concat(nabcn);

f)sbl.concat(Mabc,r);si=sl.concat("abcn);

g)sbl.append(nabcn);si=si+sl.concat("abcn);

34)1.publicclassLineUp{

publicstaticvoidmain(String[]args){

doubled=12.345;

//insertcodehere

}

}下列哪句代码放到程序的第4行，可以输出I12.3451?()

a)System.out.printf("l%7dl\nn,d);

b)System.out.printf("l%7fl\n,f,d);

c)System.out.printf("l%3.7dl\n",d);

d)System.out.printf(nl%3.7fl\n”,d);

e)System.out.printf(Hl%7.3dl\n"，d);

f)System.out.printf(nl%7.3fl\n”,d);

35)11.publicclassTest{

publicstaticvoidmain(String[]args){

intx=5;

booleanbl=true;

booleanb2=false;

if((x==4)&&!b2)

System.out.print(nl");

System.out.print("2");

if((b2=true)&&bl)

System.out.print("3");

)

}程序的输出结果是()

a)2

b)3

c)12

d)23

e)123

f)Compilationfails.

g)Anexceptionisthrownatruntime.

36)10.interfaceFoo{}

classAlphaimplementsFoo{}

classBetaextendsAlpha{}

classDeltaextendsBeta{

publicstaticvoidmain(String]]args){

Betax=newBeta();

//insertcodehere

}18.)

下列哪句代码放到第16行，可以导致一java.lang.ClassCastException()

a)Alphaa=x;

b)Foof=(Delta)x;

c)Foof=(Alpha)x;

d)Betab=(Beta)(Alpha)x;

37)22.publicvoidgo(){

Stringo="”；

z:

.for(intx=0;x<3;x++){

for(inty=0;y<2;y++){

if(x==l)break;

if(x==2&&y==l)breakz;

o=o+x+y;

)

)

System.out.println(o);

}当调用g。方法时，输出结果是什么()

a)00

b)0001

c)000120

d)000120221

38)11.staticvoidtest()throwsRuntimeException{

try(

System.out.print(ntest");

thrownewRuntimeException();

)

catch(Exceptionex){System.out.print("exception");}

)

publicstaticvoidmain(String[]args){

try{test();}

catch(RuntimeExceptionex){System.out.print(nruntime")；}

System.out.print(nendn);}程序运行结果是()

a)testend

b)Compilationfails.

c)testruntimeend

d)testexceptionend

e).AThrowableisthrownbymainatruntime

39)33.try{

//somecodehere

}catch(NullPointerExceptionel){

System.out.print(Ha");

}catch(Exceptione2){

System.out.print(,,bn);

}finally{

System.out.print("cH);

}如果程序的第34行会抛出一些异常，程序的运行结果是()

a)ab)bc)cd)ace)abc

40)31.//somecodehere

try(

//somecodehere

}catch(SomeExceptionse){

//somecodehere

}finally{

//somecodehere

}哪种情况下37行的代码会执行，请选择3个()

a)Theinstancegetsgarbagecollected.

b)Thecodeonline33throwsanexception.

c)Thecodeonline35throwsanexception.

d)Thecodeonline31throwsanexception.

e)Thecodeonline33executessuccessfully.

41)10.intx=0;

inty=10;

do{

y-；++X；

}while(x<5);

System.out.print(x+"J+y);

程序运行结果是()

a)5,6

b)5,5

c)6,5

d)6,6

42)publicclassDrink{

publicstaticvoidmain(String[largs){

booleanassertsOn=true;

assert(assertsOn):assertsOn=true;

if(assertsOn){

System.owZ.println(nassertison");

}程序运行结果是()

a)nooutput

b)nooutputassertison

c)assertison

d)assertisonAnAssertionErroristhrown.

43)11.Floatpi=newFloat(3.14f);

if(pi>3){

System.out.print(npiisbiggerthan3.")；

)

else{System.out.print(npiisnotbiggerthan3.'*);

)…

finally{

System.out.println("Haveaniceday.");

}程序运行结果是()

a)Compilationfails.

b)piisbiggerthan3

c)Anexceptionoccursatruntime.

d)piisbiggerthan3.Haveaniceday.

e)piisnotbiggerthan3.Haveaniceday.

44)1.publicclassBoxer1{

Integeri;

intx;

publicBoxer1(inty){

x=i+y;

System.out.println(x);

)

publicstaticvoidmain(String[]args){

newBoxer1(newInteger(4));

)

}运行结果是()

a)Thevalue"4"isprintedatthecommandline.

b)Compilationfailsbecauseofanerrorinline5.

c)ANullPointerExceptionoccursatruntime.

d)ANumberFormatExceptionoccursatruntime.

45)1.publicclassPerson{

privateStringname;

publicPerson(Stringname){=name;}

publicbooleanequals(Personp){

return.equals();6.}7.}

下列哪条语句是正确的()

a)TheequalsmethoddoesNOTproperlyoverridetheObject.equalsmethod.

b)Compilationfailsbecausetheprivateattributecannotbeaccessedinline5.

c)Toworkcorrectlywithhash-baseddatastructures,thisclassmustalsoimplementthe

hashCodemethod.

d)WhenaddingPersonobjectstoajava.util.Setcollection,theequalsmethodinline4will

preventduplicates.

46)1.publicclassScoreimplementsComparable{

privateintwins,losses;

publicScore(intw,int1){wins=w;losses=1;}

publicintgetWins(){returnwins;}

publicintgetLosses(){returnlosses;}

publicStringtoStringO{

retum+wins+”J+losses+”>”；

}

//insertcodehere

}下列哪句代码放到第9行，程序可以正确编译()

a)publicintcompareTo(Objecto){/*morecodehere*/}

b)publicintcompareTo(Scoreother){/*morecodehere*/)

c)publicintcompare(Scoresi,Scores2){/*morecodehere*/}

d)publicintcompare(Objectol,Objecto2){/*morecodehere*/}

47)3.publicclassBatman{

intsquares=81;

publicstaticvoidmain(String[]args){

newBatman().go();

}

voidgo(){

incr(++squares);

System.out.println(squares);

)

voidincr(intsquares){squares+=10;}

}程序运行结果是()

a)81

b)82

c)91

d)92

48)15.publicclassYippee{

publicstaticvoidmain(String[]args){

for(intx=1;x<args.length;x++){

System.out.print(args[x]+"");19.}20.}21.)

在控制台依次输入两条命令

javaYippee

javaYippee1234

程序的运行结果是()

a)Nooutputisproduced.123

b)Nooutputisproduced.234

c)Nooutputisproduced.1234

d)Anexceptionisthrownatruntime.123

e)Anexceptionisthrownatruntime.234

f)Anexceptionisthrownatruntime.1234

49)13.publicclassPass{

publicstaticvoidmain(String[]args){

intx=5;

Passp=newPass();

p.doStuff(x);

System.out.print(nmainx="+x);

)

21.voiddoStuff(intx){

System.out.print(HdoStuffx=n+x++);

)

}程序的运行结果是()

a)Compilationfails.

b)Anexceptionisthrownatruntime.

c)doStuffx=6mainx=6

d)doStuffx=5mainx=5

e)doStuffx=5mainx=6

f)doStuffx=6mainx=5

50)3.interfaceAnimal{voidmakeNoise();}

classHorseimplementsAnimal{

Longweight=1200L;

publicvoidmakeNoise(){System.out.println("whinny")；}

)

publicclassIcelandicextendsHorse{

publicvoidmakeNoise(){System.out.println(Hvinnyn);}

publicstaticvoidmain(String[]args){

Icelandicil=newIcelandic();Icelandici2=newIcelandic();

12.Icelandici3=newIcelandic();

i3=il;il=i2;i2=null;i3=il;

)

}程序运行结束后，有几个对象符合垃圾回收的条件()

a)0

b)1

c)2

d)3

e)4

f)6

51)11.String[]elements={"for","tea","too"};

Stringfirst=(elements.length>0)elements[0]:null;

程序运行结果是()

a)Compilationfails.

b)Anexceptionisthrownatruntime.

c)Thevariablefirstissettonull.

d)Thevariablefirstissettoelements[0].

52)31.classFoo{

publicinta=3;

publicvoidaddFive(){a+=5;System.out.print(nf");}

)

classBarextendsFoo{

publicinta=8;

publicvoidaddFive(){this.a+=5;System.out.print("b");}

)

主方法执行下列语句

Foof=newBar();

f.addFive();

System.out.println(f.a);程序运行结果是()

a)b,3

b)b,8

c)b,13

d)f,3

e)f,8

f)f,13

g)Compilationfails.

h)Anexceptionisthrownatruntime.

53)1.classClassA{

publicintnumberOflnstances;

protectedClassA(intnumberOflnstances){

this.numberOflnstances=numberOflnstances;

)

)

publicclassExtendedAextendsClassA{

privateExtendedA(intnumberOflnstances){

uper(numberOflnstances);

)

publicstaticvoidmain(String[]args){

ExtendedAext=newExtendedA(420);

System.out.print(ext.numberOflnstances);

)

}下列哪句描述是正确的()

a)420istheoutput.

b)Anexceptionisthrownatruntime.

c)Allconstructorsmustbedeclaredpublic

d)ConstructorsCANNOTusetheprivatemodifier.

e)ConstructorsCANNOTusetheprotectedmodifier.

54)11.classClassA{}

classClassBextendsClassA{}

classClassCextendsClassA{}

and:

ClassApO=newClassAQ;

ClassBpl=newClassB();

ClassCp2=newClassC();

ClassAp3=newClassB();

ClassAp4=newClassC();

下边哪句代码是正确的，请选择3个()

a)pO=pl；

b)pl=p2;

c)p2=p4;

d)p2=(ClassC)pl;

e)pl=(ClassB)p3;

f)p2=(ClassC)p4;

55)5.classThingy{Meterm=newMeter();}

classComponent{voidgo(){System.out.print(',cn);}}

classMeterextendsComponent{voidgo(){System.out.print(nmH);}}

9.classDeluxeThingyextendsThingy{

publicstaticvoidmain(String[]args){

DeluxeThingydt=newDeluxeThingyO;

dt.m.goO;

Thingyt=newDeluxeThingyO;

t.m.go();

)

}下边哪句描述是正确的，请选择2个()

a)Theoutputismm.

b)Theoutputisme.

c)Componentis-aMeter.

d)Componenthas-aMeter.

e)DeluxeThingyis-aComponent.

f)DeluxeThingyhas-aComponent.

56)10.interfaceJumper{publicvoidjump();}...

classAnimal{}...

classDogextendsAnimal{

Tailtail;

}••.

classBeagleextendsDogimplementsJumper{

publicvoidjump(){}

}...

classCatimplementsJumper{

publicvoidjump(){}

}下边哪句描述是正确的，请选择3个()

a)Catis-aAnimal

b)Catis-aJumper

c)Dogis-aAnimal

d)Dogis-aJumper

e)Cathas-aAnimal

f)Beaglehas-aTail

g)Beaglehas-aJumper

57)1.importjava.util.*;

publicclassWrappedString{

privateStrings;

publicWrappedString(Strings){this.s=s;}

publicstaticvoidmain(String[]args){

HashSeths=newHashSet();

WrappedStringwsl=newWrappedStringC^ardvark1');

WrappedStringws2=newWrappedString(HaardvarkH);

Stringsi=newStringCaardvark11);

Strings2=newString("aardvarkn);

hs.add(wsl);hs.add(ws2);hs.add(sl);hs.add(s2);

System.out.println(hs.size());}}运行结果是()

a)0

b)1

c)2

d)3

e)4

f)Compilationfails.

d)Anexceptionisthrownatruntime.

58)2.importjava.util.*;

publicclassGetlnLine{

publicstaticvoidmain(String[]args){

PriorityQueuepq=newPriorityQueue();

pq.add("banana");

pq.add("pearn);

pq.addC'apple");

System.out.println(pq.poll()+””+pq.peek());

运行结果是（）

a)applepear

b)bananapear

c)appleapple

d)applebanana

59)3.importjava.util.*;

publicclassMapit{

publicstaticvoidmain(String[]args){

Setset=newHashSet();

Integeri1=45;

Integeri2=46;

set.add(il);

set.add(il);

set.add(i2);System.out.print(set.size()+"”)；

set.remove(il);System.out.print(set.size()+"

i2=47;

set.remove(i2);System.out.print(set.size()+"");

}16.}程序运行结果是()

a)210

b)211

c)321

d)322

60)12.importjava.util.*;

publicclassExplorer1{

publicstaticvoidmain(String[]args){

TreeSets=newTreeSet();

TreeSetsubs=newTreeSet();

for(inti=606;i<613;i++)

if(i%2==0)s.add(i);

subs=(TreeSet)s.subSet(608,true,611,true);

.s.add(609);

System.out.println(s+"“+subs);

}23.}运行结果是()

a)Compilationfails.

b)Anexceptionisthrownatruntime.

c)[608,609,610,612][608,610]

d)[608,609,610,612][608,609,610]

e)[606,608,609,610,612][608,610]

f)[606,608,609,610,612][608,609,610]

61)3.importjava.util.*;

publicclassQuest{

publicstaticvoidmain(String[]args){

String[]colors={"blue"，"red"，"green"，"yellow"，"orange"};

Arrays.sort(colors);

ints2=Arrays.binarySearch(colors,norange");

ints3=Arrays.binarySearch(colors,"violet");

System.out.println(s2+""+s3);

}12.}运行结果是()

a)2-1

b)2-4

c)2-5

d)3-1

e)3-4

f)3-5

g)Compilationfails.

h)Anexceptionisthrownatruntime

62)34.HashMapprops=newHashMapO;

props.put("key45","somevalue");

props.put("keyl2","someothervalue");

props.put("key39","yetanothervalue");

.Sets=props.keySet();

//insertcodehere

下列哪行代码放到39行是正确的()

a)Arrays,sort(s);

b)s=newTreeSet(s);

c)Collections.sort(s);

d)s=newSortedSet(s);

63)1.publicclassTestOneimplementsRunnable{

publicstaticvoidmain(String[]args)throwsException{

Threadt=newThread(newTestOne());

t.start();

System.out.print(',Startedn);

t-join();

System.out.print(HCompleten);

)

publicvoidrun(){

for(inti=0;i<4;i++){

System.out.print(i);

}13.}14.}语系那个结果是()

a)Compilationfails.

b)Anexceptionisthrownatruntime.

c)Thecodeexecutesandprints"StartedComplete*'.

d)Thecodeexecutesandprints"StartedCompleteO123”

e)Thecodeexecutesandprints"Started0123Complete".

64)下边哪行代码是正确的，请选择3个()

a)privatesynchronizedObjecto;

b)voidgo(){synchronized(){/*codehere*/}

c)publicsynchronizedvoidgo(){/*codehere*/}

d)p