Java程序员认证考试题库

第一局部根底知识练习本章对应于?学生指南?各章的内容分别提供了练习题集，包括：a•第二章数据类型和运算符第三章流程控制与数组抽象类与接口制流•第十一章使用泛型和集合框架•第十二章基于Swing的图形用户界面(GUI)设计•第十三章Java事件驱动编程第一章练习题〔Java入门〕A.Java编程语言C.JavaEE扩展APIA.JDK中包含了B.JRE中包含了C.JRE中包含了D.JDK中包含了MJREDKJVMVMJREJRE,JRE中包含了JVM3.以下哪个工具可以编译A.javacB.jdbC.javadocD.junitA.java.langB.javax.servlet.C.java.io6•使用JDK工具生成的Java文档的文件格式是?c进制格式A.JVM运行于操作系统之上，它依赖于操作系统BJVM无关AD以下关于AJavaHotSpot.JavaHotSpotaot技术，它只对程序的局部字节码进行优化是一种热编译.JavaHotSpot技术，它会对程序的全部字节码进行优化HA.:PATHA.省略号B.当前目录C.所有目录A.执行类中的代码一＞装载类一＞校验类B.校验类一＞装载类一＞执行类中的代码C.装载类一＞执行类中的代码一＞校验类D＞校验类一＞执行类中的代码B.Java源文件的文件名应与文件中的类名一致C.Java字节码文件的扩展名应为.javaAD第二章练习题〔数据类型和运算符〕C.doubleD.booleanA.\uO3A6C.OxABBCD.203.以下哪项不是有效的标识符?serNameC.$changeA行注释C./*行注释CinstanceofD.volatile6.现有如下五个声明:Linel:inta_really_really_really_long_variable_name=5;larslineint%opercent=9;A.Line1B.Line3C.Line42.staticintx=l；3.publicTop(inty){x*=3;}4.}5.classMiddleextendsTop{6.publicMiddle(){x+=1;)7.publicstaticvoidmain(String[]args){8.Middlem=newMiddle();9.System.out.println(x);10.}B.2(A)8.Passerf2.staticfinalintX=5；3.publicstaticvoidmain(String[]args){4.newPasser().go(x);5.System.out.print(x);6,)7.voidgo(intx){8.System.out.print(x++);9.}A55tringSystemout.print(w2==w);6．}7.staticWrenchgo(Wrenchwrl,Wrenchwr2){8.Wrenchwr3=wrl;wrl=wr2;wr2=wr3;wr3;}7.publicstaticvoidmain(String[]args){8.Wrench2w=newWrench2();ISystemoutprintwsize13.staticWrench2go(Ws){14.S=12;A.11B.12D抛出publiCstatiCvoidmain(String[]args){shortabC}以上代码中，哪一句是错误的？}}A.a=1：B.C=a+b；abCC.9StringsB.579C.编译错误A.IntegerB.DoubleC.FloatD.Character(D)15.现有:1.classTest4{2.publicstaticvoidmain(String[]args){3.booleanX=true;4.booleany=false;5.shortZ=42;6.7.if((z++==42)&&(y=true))z++;8.if((x=false)||(++z==45))z++9.10.System.out.printl"z=〞+z);II.n(}12.}A.Z=42B.z=44C.Z=45D.z=46第二章练习题参考答案1B2A3B4ACD5B6D7D8A9B第三章练习题第三章练习题〔流程控制与数组〕publicstaticvoidmain(String[]args){for(inti=0;i<lO;i++){if(i==3)printi}}程序运行后的输出是哪项？}}classTestApp{publicstaticvoidmain(String[]System.out.println("x>l");args){elseifx5)System.out.println("x>5");elseifx10)System.out.println("x<lO");elseifx29)System.out.println("x<29");}}上述程序运行后的结果是哪项？A．x>5}assTestApppublicstaticvoidmain(String[]args){int[5]myarray={10,11,12,13,14);Systemoutprintln("sum="+sum);}}}classTestApp{publicstaticvoidmain(String[]args){intX=5：lt)}))A.一季度c三季度以上DmyArray采取以下编码：2.publicstaticvoidmain(String[]args){3.booleanstate=false;4.inti=2；if++i>2)＆＆(state=true))6.i++;7.if((++i>4)ll(state=false))8.i++;9.System.out.println(i);10.}654．Sx3=newInteger(5);8.system..ut.print(x1.equals(x));9.system..ut.print(xl==x);xequalsxl11.system..ut.print(x2==xl);12-system..ut.print(x2==x3);13-system..ut.print(x2.equals(x3))A编译失败CtruetruetruetruetruetrueE.truefalsetruefalsefalsetruelicstaticVidmainstring{args){sA.X=6C.X=2A.Z=21IDBC4CD5B6B7D8A9C11C12CA14B15B第四章练习题〔封装〕A•类就是对象，对象就是类，实例是对象的另一个名称，三者没有差异B.对象是类的抽象，类是对象的具体化，实例是对象的另一个名称C•类是对象的抽象，对象是类的具体化，实例是类的另一个名称D.类是对象的抽象，对象是类的具体化，实例是对象的另一个名称gnameldoubleamount="Mike";))namedoubleamount;Stringname="Mike,,,doubleamount=1000.0;)epositvoiddeposit()；}C．classAccountfvoiddeposit(){))DclassAccountfvoiddeposit有关类声明的代码片段，哪一项为A.packageschool;)ltaddintaA.publicintadd(longa);Bpublicvoidadd(inta)jC.publicvoidadd(longa);D.publicintadd(floata);8．我们定义一个Account类来描述银行账户，银行账户有账户名、金Account(Stringname)()))}Account(doubleamount){))))))Account(Stringname){))))Account(Stringname){)3.'publicstaticvoidmain(String[]args){5.Banana2b=newBanana2()；C.3D.2C.3D.2)DirectionEAST,SOUTH,WEST,NORTH)A.DirectionDirection=EAST;B.Directiondirection=Direction.WEST;C.inta-Direction.NORTH;nDirectiondirection=2；(Strings){returns+s；)}再定义另一个类Demo:l.//insertcodeherepublicclassDemo{3.publicstaticvoidmain(String[]args){4.System.out.println(twice("Hello"));BimportutilsRepC.importstaticutils.Rep.twice;staticimportutilsReptwiceintj=10;classCinner{publicvoidmymethod(){//Here}}}}B.y||y|A.packagey；C.importcom.x.y.*;omx2.publicclassX{3.publicstaticvoiddoX(){System.out.print("doX");}2.publicstaticvoidmain(String[]args){5.}哪两行分别插入到类Find的第3行将编译并产生输出“doX〞？〔选doXD11BABDCD第五章练习题〔继承〕A.可以创立更为特殊的类型B.消除重复代码C.执行效率高B.publicvoidchange(intx,inty){}C.publicvoidchange(intx){}D.publicvoidchange(Strings){}4．如果想要一个类不能被任何类继承的话，需要使用哪个关键字来修A.abstractC.staticD.final5．为了使得System.out.println()输出对象引用的时候得到有意义的信我oStringpublicclassPetpublicclassCatextendsPet{)执行代码CatcnewCatA.Petp=(Pet)c运行错误BPetpPetc译错误C.Petp=(Pet)c止常执行D.以上都不对}}}speak(){System.out.print("Cat")}}icclassDogextendsPetpublicvoidspeakSystem.out.print("Dog");}执行代码}Pet[]p={newCat(),newDog(),nexPet()};for(inti=O;i<p.length;i++)p[i].speak()；C.CatDogDog2.classHarrierextendsDog{)4.classDogTest{riererd11.}}2.classCat{atc5.classSubCatextendsCat{SubCatthis8.publicstaticvoidmain(String[]args){9.SubCats=newSubCat();10.}A.cat5tcableD.cablecat51.classGuy{Stringgreet(){return"hi";}}Guy(String2.classCowboyextendsgreet()(return3.classSurferextendsGuy(Stringgreet()(return"dude!";}}6.publicstaticvoidmain(String[]args){7.Guy[]guys=(newGuy(),newCowboy(),newSurfer()};Systemoutprintg.greet()};A.hihowdydude!B.运行时异常被抛出。2.intdolt(longx){return3;}3.}5.classUnderextendsOver{shortdolt(inty){return4;}intdolt(longXrlongy){return4;}privateintdolt(shorty){return4;}protectedintdolt(longx){return4;}A.1B.2C.3D.42.Beverage(){System.out.print("beverage");}3.}4.classBeerextendsBeverage{5.publicstaticvoidmain{string[]args){6.Beerb=newBeer(14);7.}8.publicintBeer(intx){9.this();10.System.out.print("beerl");11.}12.publicBeer(){System.out.print("beer2");}13.}结果是什么?A.beerlbeverageC.beveragebeer2beerl13.现有:1.classBird{2.voidtalk(){System.out.print("chirp");}3.}4.classParrot2extendsBird{5.protectedvoidtalk(){System.out.print("hello");6.publicstaticvoidmain(String[]args){7.Bird[]birds={newBird(),newParrot2()};8.for(Birdb:birds)9.b.talk();10.}11.}结果是什么?A.chirpchirpphello2.SuperFoodoStuff(intx){3.returnnewSuperFoo();}7.classFooextendsSuperFoo{ontx{returnnewFoo();}SuperFoodoStuff(inty){returnnewSuperFoo();A.1B.2C.33.protectedHorseRadish(intx){4.System.out.println("bokchoy");7.classWasabiextendsHorseRadish{8.publicstaticvoidmain(String[]args)(9.Wasabiw-newWasabi();A.protectedHorseRadish(){this(42)；}tedHorseRadishtD.protectedHorseRadish(){newHorseRadish(42);}SB6A7D8D9C1D第六章练习题〔抽象类与接口〕A.抽象类中一定含有抽象方法C.抽象类既能被实例化也能被继承D.抽象类中不能有构造方法〕A.抽象方法和普通方法一样，只是前面多加一个修饰符asbtractB.抽象方法没有方法体c.抽象方法可以包含存任何类中D.包含抽象方法的类的具体子类必须提供具体的覆盖方法B.一个类可以实现多个接口C.类实现接口时必须实现其中的方法D.接口不能被继承B.publicinterfaceAimplementsB{)D.abstractinterfaceD{)B.1voideat)；5.//insertcodehere7.publicclassHouseCatimplementsFeline{interfaceFelineextendsAnimal()interfaceFelineextendsAnimal{voideat();interfaceFelineextendsAnimal{voideat()A.0B.1aceWeightclassBoatextendsColor,extendsWeight{}tendsColorandWeightclassBoatextendsColor,Weight{}lementsWeightlementsColorandWeightclassBoatimplementsColor,Weight{}A.0B.12.protectedabstractStringgetRGB();eturnblueprotectedStringA.0C.2D.35.publicclassBlue2extendsColor2{A.OB.1C.2D32.staticintX=l；5.classMiddleextendsTop{6.publicMiddle(){x+=l;}7.publicstaticvoidmain(String[]args){8.Middlem=newMiddle();Systemoutprintln(x)j10.}A.2C.42.publicclassX{3.publicstaticvoiddoX(){System.out.print("doX");}2.classFind{3.publiCstaticvoidmain(String[]args){4.XmyX=newX();myX.doX();5X.doX()；．68xXaoX)：x.XmyX2=newx}'；1.classTree{2.privatestaticStringtree="tree";3.StringgetTree(){returntree;}4.}5.classElmextendsTree{6.privatestaticStringtree="elm";7.publicstaticvoidmain(String[]args){8.newElm().go(newTree());9.}10.voidgo(Treet){11.Strings=t.getTree()+Elm.tree+tree+Elm().getTree());12.System.out.println(s);结果为:A.elmelmelmelmB.treeelmelmelmC.treeelmelmtreeDtreeelmtreeelmrfaceAnimal2.voideat();5.//insertcodehere7.publicclassHouseCatextendsFeline{8.publicvoideat(){}9.}和五个申明abstractclassFelineimplementsAnimal{}abstractclassFelineimplementsAnimal{voideat();}abstractclassFelineimplementsAnimal{publicvoideat();}abstractclassFelineimplementsAnimal{publicvoideat(){}}))abstractclassFelineimplementsAnimal{abstractpublicvoideat();}A.1C3lassAimplementsIclassCextendsA{ctvoidloadA.publicclassEmployeeimplementsInfoextendsData{)B.publicclassEmployeeextendsInf.implementsData{publicvoidload().publicclassEmpl.yeeimplementsInfextendsData{publicvoidData.1oad(){*dosomething*／}publicvoidload(){／*dosomething*)publicclassEmployeeextendsInfimplementsData{cvoiddosomething15.以下代码正确的选项是哪项?A.publicclassSessionimplementsRunnable,Clonable{publicvoidrun();publicObjectclone();un{/*dosomething*/}publicObjectclone(){/*makeacopy*/}C.publicabstract}classSessionimplementsRunnable,Clonable{pu)olicvoidrun(){/*dosomething*/}publicObjectclone(){/*makeacopy*/}implementsRunnable,implementsClonable{publicvoidrun(){/*dosomething*/}publicObjectclone(){/*makeacopy*/}}11C第七章练习题〔多态〕A•父类的引用指向子类的实例是一种多态B子类的实例是一种多态c.接口的引用指向实现该接口类的实例是一种多态D实例是一种多态c绑定gA.trueB.falseC.1D.04.求平方根方法publicstaticdoublesqrt(doublea)可以传递的参数类A.byteD.long5.涉及类MyClass的方法签名足publicvoidfind(MyClassa〕，那么该A.MyClass类的类型sCObject型ceofcontent){System.out.println("Write"+content);}}classRubberPencilextendsPencil{publicvoiderase(Stringcontent){System.out.println("Erase"+content);}}}}A.WriteHelloWriteHelloc译错误}content){System.out.println("Write"+content)；}}classRubberPencilextendsPencil{publicvoidwrite(Stringcontent){System.out.println("RubberWrite"+content);}publicvoiderase(Stringcontent){System.out.println("Erase"+content);}}A.WriteHelloberWriteHelloA.静态方法privatecontent){System.out.println("Write",+content){}ring}content){System.out.println("RubberWrite"+content)；}tlnErasecontent}Pencilpen=new}cclassTestA{publicvoidstart(){System.out.println("TestA");}}publicclassTestBextendsTestA{utprintlnTestBlicstaticvidmainstringargs}}}C.编译失败ClassA{publiCStringname="a"}ClassBextendsA{publiCStringname="b"}执行如下代码后的结果是哪Aa=newB()；Systemoutprintln();c.编译失败2classAimplementsF{}3classBextendsA{}4classCextendsB{5publicstaticvoidmain(String[]args){6Bb=newB()；8}9}returnreturn.A.Aa=b; Guyg2=newCowboy()；{}11.A.hihiouch!12.B.ouch!howdyouch!Chihowdyouch!assAsClassCextendsClassAClassBplnewClassB；ClassCpnewClassC；ClassApnewClassB；ClassApnewClassC；2AB3A4ABD5AB6C7C8B9ABC10D11B12A13B14B15AEF11第八章练习题〔异常〕A•运行时异常和异常D.finally必须有A.SQLExceptionIOExceptionptionD.OutOfMemoryError5.假设有自定义异常类ServiceException，那么抛出该异常的语句正确A.raiseServiceExceptionBthrownewServiceException()C.throwServiceExce