OracleOCA认证考试练习真题题库二

试卷科目：OracleOCA认证考试练习OracleOCA认证考试练习真题题库二PAGE"pagenumber"pagenumber/SECTIONPAGES"numberofpages"numberofpagesOracleOCA认证考试练习真题题库二第1部分：单项选择题，共124题，每题只有一个正确答案,多选或少选均不得分。[单选题]1.ClassProduct{Doubleprice;}PublicclassTest{PublicvoidupdetePrice(Productproduct,doubleprice){Price=price*2;Product.price=product.price+price;}Publicstaticvoidmain(String[]arge){Productprt=newProduct();Prt.price=200;DoublenewPrice=100;Testt=newTest();T.updetePrice(prt,newPrice);System.out.println(prt.price+":"+newPrice);}}A)200.0:100.0B)400.0:200.0C)400.0:100.0D)Compilationfails答案:C解析:[单选题]2.If(aval++<10){System.out.println(aval+"HelloUniverse");}else{System.out.println(aval+"Hell0World");}WhatistheresultiftheintegeraVaris9?A)10HelloWorld!B)10HelloUniverse!C)HelloWorld!D)Compilationfails.答案:B解析:[单选题]3.publicstaticvoidmain(String[]args){Stringdate=LocalDateparse("2014-05-04")format(DateTimeFormatterISO_DATE_TIME);System.out.println(date);}Whatistheresult?A)May04,2014T00:00:00.000B)2014-05-04T00:00:00.000C)5/4/14T00:00:00.000D)Anexceptionisthrownatruntime.答案:D解析:[单选题]4.publicstaticvoidmain(String[]args){Shorts1=200;Integers2=400;Longs3=(long)s1+s2;//linen1;Strings4=(String)(s3*s2);//linen2;}Whatistheresult?A)Sumis600B)Compilationfailsatlinen1.C)Compilationfailsatlinen2.D)AClassCastExceptionisthrownatlinen1.E)AClassCastExceptionisthrownatlinen2.答案:C解析:[单选题]5.classVehicle{Stringtype="4w";intmaxSpeed=100;Vehicle(Stringtype,intmaxSpeed){this.type=type;this.maxSpeed=maxSpeed;}}classCarextendsVehicle{Stringtrans;Car(Stringtrans){//linen1this.trans=trans;}Car(Stringtype,intmaxSpeed,Stringtrans){super(type,maxSpeed);this(trans);//linen2}}}Andgiventhecodefragment:Carc1=newCar("Auto");Carc2=newCar("4w",150,"Manual");System.out.println(c1.type+""+c1.maxSpeed+""+c1.trans);System.out.println(c2.type+""+c2.maxSpeed+""+c2.trans);Whatistheresult?A)4W100Auto4W150ManualB)Null0Auto4W150ManualC)Compilationfailsonlyatlinen1D)Compilationfailsonlyatlinen2E)Compilationfailsatbothlinen1andlinen2答案:E解析:[单选题]6.publicstaticvoidmain(String[]args){StringBuildersb=newStringBulider(5);Strings="";If(sb.equals(s)){System.out.println("Match1");}elseif(sb.toString().equals(s.toString()){System.out.println("Match2");}else{System.out.println("NOMatch");}}Whatistheresult?A)Match1B)Match2C)NoMatchD)ANullPointerExceptionisthrownatruntime.答案:B解析:[单选题]7.Given:Publicstaticvoidmain(String[]args){Stringta="A";Ta=ta.concat("B");Stringtb="C";Ta=ta.concat(tb);Ta.replace('C','D');Ta=ta.concat(tb);System.out.println(ta);}Whatistheresult?A)ABDCB)ABCCC)ABCDD)ACDE)ABC答案:B解析:[单选题]8.Given:ClassCD{intr;CD(intr){this.r=r;}}ClassDVDextendsCD{intc;DVD(intr,intc){//linen1}}Andgiventhecodefragment:DVDdvd=newDVD(10,20);Whichcodefragmentshouldyouuseatlinen1toinstantiatethedvdobjectsuccessfully?您应该在第n1行使用哪个代码片段来成功实例化dvd对象?A)super.r=r;this.c=c;B)uper(r);this(c);C)super(r);this.c=c;D)this.c=r;super(c);答案:C解析:[单选题]9.Given:Inta[]={1,2,3,4,5};For(XXX){System.out.print(a[e]);}Whichoptioncanreplacexxxtoenablethecodetoprint135?A)inte=0;e<=4;e++B)inte=0;e<5;e+=2C)inte=1;e<=5;e+=1D)inte=1;e<5;e+=2答案:B解析:[单选题]10.Whichstatementbestdescribesencapsulation?A)Encapsulationensuresthatclassescanbedesignedsothatonlycertainfieldsandmethodsofanobjectareaccessiblefromotherobjects.封装确保可以设计类,以便只有对象的某些字段和方法可以从其他对象访问。B)Encapsulationensuresthatclassescanbedesignedsothattheirmethodsareinheritable.封装确保类可以被设计成它们的方法是可继承的。C)Encapsulationensuresthatclassescanbedesignedwithsomefieldsandmethodsdeclaredasabstract封装确保类可以在设计时将某些字段和方法声明为抽象D)EncapsulationensuresthatclassescanbedesignedsothatifamethodhasanargumentMyTypex,anysubclassofMyTypecanbepassedtothatmethod.封装确保可以设计类,这样如果一个方法有MyTypex参数,MyType的任何子类都可以传递给该方法。答案:A解析:[单选题]11.Giventhecodefragment:Stringshirts[][]=newString[2][2];Shirts[0][0]="red";Shirts[0][1]="blue";Shirts[1][0]="small";Shirts[1][1]="medium";Whichcodefragmentprintsred:blue:small:medium:?A)for(intindex=0;index<2;++index){For(intidx=0;idx<index;++idx){System.out.print(shirts[index][idx]+":");}}B)for(intindex=1;index<2;index++){For(intidx=1;idx<2;idx++){System.out.print(shirts[index][idx]+":");}}C)for(Stringc:colors){For(Strings:sizes){System.out.println(s+":");}}D)for(intindex=0;index<2;){For(intidx=0;idx<2;){System.out.print(shirts[index][idx]+":");Idx++;}Index++;}答案:D解析:[单选题]12.Giventhecodefragment:PublicclassTest{VoidreadCard(intcardNo)throwsException{System.out.println(ReadingCard?);}VoidcheckCard(intcardNo)throwsRuntimeException{//linen1System.out.println(?CheckingCard?);}Publicstaticvoidmain(String[]args){Testex=newTest();IntcardNo=12344;Ex.checkCard(cardNo);//linen2Ex.readCard(cardNo);//linen3}}Whatistheresult?A)ReadingCardCheckingCardB)Compilationfailsonlyatlinen1.C)Compilationfailsonlyatlinen2.D)Compilationfailsonlyatlinen3.E)Compilationfailsatbothlinen2andlinen3.答案:D解析:[单选题]13.Giventhecodefragment:3\publicstaticvoidmain(String[]args){4\intx=5;5\while(isAvailable(x)){6\System.out.println(x);7\8\}9\}10\11\publicstaticbooleanisAvailable(intx){12\returnx-->0?true:false;13\}Whichmodificationenablesthecodetoprinto54321?A)Replaceline6withSystem.out.print(--x);B)Atline7insertx--;C)Replaceline6with--x;andatline7insertsysytem.out.print(x);D)Replaceline12withreturn(x>0)?false:true;答案:B解析:[单选题]14.Giventhecodefragment:Publicstaticvoidmain(String[]args){Intx=5;While(isAvailable(x)){System.out.println(x);}}PublicstaticbooleanisAvailable(intx){Returnx-->0?true:false;}Whichmodificationenablesthecodetoprint54321?A)Replaceline6withSystem.out.print(--x);B)Atline7,insertx--;C)Replaceline6with--x;and,atline7,insertsystem,out.print(x);D)Replaceline12Withreturn(x>0)?false:true;答案:B解析:[单选题]15.Giventhecodefragment:Publicstaticvoidmain(String[]args){Booleanopt=true;Switch(opt){Casetrue:System.out.println("True");Break;Default:System.out.println("****");}System.out.println("Done");}WhichmodificationenablesthecodefragmenttoprintTrueDone?A)Replaceline5WithStringopt="true";Replaceline7withcase"true":B)Replaceline5withbooleanopt=l;Replaceline7withcase1:C)Atline9,removethebreakstatement.D)Removethedefaultsection.答案:A解析:[单选题]16.Giventhecodefragment:Publicstaticvoidmain(String[]args){Intnum=5;Do{System.out.println(num--+"");}while(num==0)}Hatistheresult?A)543210B)54321C)421D)5E)Nothingisprinted答案:D解析:[单选题]17.Giventhecodefragment:Publicstaticvoidmain(String[]args){Intx=100;Inta=x++;Intb=++x;Intc=x++;Intd=(a<b)?(a<c)?a:(b<c)?b:c;System.out.println(d);}Whatistheresult?A)100B)101C)102D)103E)Compilationfails答案:E解析:[单选题]18.Giventhecodefragment:Publicstaticvoidmain(String[]args){String[][]chs=newString[5][2];Chs[0]=newString[2];Chs[0]=newString[5];Inti=97;For(inta=0;a<chs.length;a++){For(intb=0;b<chs.length;b++){Chs[a][b]=""+i;I++;}}For(String[]ca:chs){For(Stringc:ca){System.out.println(c);}System.out.println();}WhatistheresultA)CompilationfailsB)AnArrayIndexOutOfBoundsExceptionisthrowatruntimeC)979899100nullnullnullD)ANullPointerExceptionisthrownatruntimeE)979899100101102103答案:B解析:[单选题]19.Giventhecodefragment:Publicstaticvoidmain(String[]args){List<String>names=newArrayList<>();Names.add("Robb");Names.add("Bran");Names.add("Rick");Names.add("Bran");If(names.remove("Bran")){Names.remove("jon");}System.out.println(names);}WhatistheresultA)[Robb,Rick,Bran]B)[Robb,Rick,Bran]C)[Robb,Rick,Bran]D)[Robb,Rick,Bran]答案:A解析:[单选题]20.Giventhecodefragment:ClassA{PublicA(){System.out.print("A");}}ClassBextendsA{PublicB(){//linen1System.out.print("B");}}ClassCextendsB{PublicC(){//linen2System.out.print("C");}Publicstaticvoidmain(String[]args){Cc=newC();}}Whatistheresult?A)CBAB)CC)ABCD)Compilationfailsatlinen1andlinen2答案:C解析:[单选题]21.ClassX{Inti;Staticintj;}Publicstaticvoidmain(String[]args){Xx1=newX();Xx2=newX();X1.i=3;X2.j=4;X1.i=5;X2.j=6;System.out.println(X1.i+""+X2.j+""+X1.i+""+X2.j);}Whatistheresult?A)3456B)3656C)3436D)5456答案:B解析:[单选题]22.Giventhecodefragment:PublicclassTest{Publicstaticvoidmain(String[]args){insertcodehere*/Array[0]=10;Array[1]=20;System.out.println(array[0]+":"+array[1]);}}Codefragment,wheninsertedatline3,enablesthecodetoprint10:20?A)int[]arrayn=newint[2];B)int[]array;array=newint[2];C)intarray=newint[2];D)intarray[2];答案:B解析:[单选题]23.Giventhecodefragment:Publicstaticvoidmain(String[]args){String[]arr={"A","B","C","D"};For(inti=0;i<arr.length;i++){System.out.println(arr[i]+"");If(arr[i].equals("C")){Continue;}System.out.println("Woekdone");Break;}}Whatistheresult?A)ABCWorkdoneB)ABCDWorkdoneC)AWorkdoneD)Compilationfails答案:C解析:[单选题]24.GiventhecodefromtheGreeting.Javafile:PublicclassGreeting{Publicstaticvoidmain(String【】args){System.out.println(?hello?+args[0]);}}WhichsetofcommandsprintsHelloDukeintheconsole?A)javacGreetingjavaGreetingDuckB)javacGreeting.javaDuckjavaGreetingC)javacGreeting,javaJavaGreetingDuckD)javaGreeting.javajavaGreeting.classDuck答案:C解析:[单选题]25.Given:PublicclassAlpha{Intns;Staticints;Alpha(ints){If(s<ns){S=ns;This.ns=ns;}}VoiddoPrint(){System.out.println("ns="+ns+"s="+s);}}PublicclassTestA{Publicstaticvoidmain(String[]args){Alpharef1=newAlpha(50);Alpharef2=newAlpha(125);Alpharef3=newAlpha(100);Ref1.doPrint();Ref2.doPrint();Ref3.doPrint();}}Whatisthisresult?Ans=50s=125ns=125s=125ns=100s=125Bns=50s=125ns=125s=125ns=0s=125Cns=50s=125ns=125s=125ns=100s=100Dns=50s=125ns=125s=125ns=0s=125Whatistheresult?A)OptionAB)OptionBC)OptionCD)OptionD答案:B解析:[单选题]26.Giventhecodefragment:Publicclasstest{Publicstaticvoidmain(String[]args){Intii=0;Intjj=7;For(ii=0;ii<jj-1;ii=ii+2){System.out.println(ii+"");}}}Whatistheresult?A)24B)0246C)024D)Compilationfails答案:C解析:[单选题]27.Giventhecodefragment:AssumethatthesystemdateisJune20,2014.Whatistheresult?LocalDatedate1=LocalDate.now();LocalDatedate2=LocalDate.of(2014,6,20);LocalDatedate3=LocalDate.parse("2014-06-20",DateTimeFormatter.ISO_DATE);System.out.println("date1="+date1);System.out.println("date2="+date2);System.out.println("date3="+date3);AssumethatthesystemdateisJune20,2014.Whatistheresult?A)OptionAAdataParseExceptionisthrowatruntimeB)OptionBdata1=2014-06-20Data2=2014-06-20Data3=2014-06-20C)OptionCData1=06/02/2014Data2=2014-06-20Data3=Jun20,2014D)OptionDCompilationfails答案:B解析:[单选题]28.Giventhecodefragment:7\StringBuildersb1=newStringBuilder("Duke");8\Stringstr1=sb1.toString();9\//insertcodehere10\System.out.print(str1==str2);Whichcodefragment,wheninsertedatline9,enablesthecodetoprinttrue?A)Stringstr2=sb1.toString();B)Stringstr2=newString(str1);C)Stringstr2="Duke";D)Stringstr2=str1;答案:D解析:[单选题]29.Giventhecodefragment:PublicclassTest{staticintcount=0;inti=0;publicvoidchangeCount(){while(i<5){i++;count++;}}Publicstaticvoidmain(String[]args){Testcheck1=newTest();Testcheck2=newTest();Check1.changeCount();Check2.changeCount();System.out.print(check1.count+":"+check2.count);}}Whatistheresult?A)CompilationfailsB)5:10C)10:10D))5:5答案:C解析:[单选题]30.Given:PublicclassTest{Publicstaticvoidmain(String[]args){If(args[O].equals("Hello")?false:true)System.out.println("success");}else{System.out.println("Failure");}}}Andgiventhecommands:JavacTest.JavaJavaTestHelloWhatistheresult?A)SuccessB)FaliureC)Compilationfails.D)Anexceptionisthrownatruntime.答案:B解析:[单选题]31.给定以下代码:Publicstaticvoidmain(String[]args){String[]planets={"Mercury","Venus","Earth","Mars"};System.out.println(planets.length);System.out.println(planets[1].length());}输出是什么?A)44B)35C)47D)54E)45F)421答案:E解析:[单选题]32.给定:Acc.java:Packagep1;PublicclassAcc{intp;privateintq;protectedintr;publicints;}Test.java:Packagep2;Importp1.Acc;PublicclassTestextendsAcc{publicstaticvoidmain(String[]args){Accobj=newTest();}}Whichstatementistrue?A)Bothpandsareaccessiblebyobj.B)Onlysisaccessiblebyobj.C)Bothrandsareaccessiblebyobj.D)p,r,andsareaccessiblebyobj.答案:B解析:[单选题]33.给定:Base.java:ClassBase{publicvoidtest(){System.out.println("Base");}}DerivedA.java:ClassDerivedAextendsBase{publicvoidtest(){System.out.println("DerivedA");}}DerivedB.java:ClassDerivedBextendsDerivedA{publicvoidtest(){System.out.println("DerivedB");}publicstaticvoidmian(String[]args){Baseb1=newDerivedB();Baseb2=newDerivedA();Baseb3=newDerivedB();b1=(Base)b3;Baseb4=(DerivedA)b3;b1.test();b4.test();}}结果是什么?A)BaseDerivedAB)BaseDerivedBC)DerivedBDerivedBD)DerivedBDerivedAE)AclasscastExceptionisthrownatruntime.答案:C解析:[单选题]34.给定代码片段:Publicstaticvoidmain(String[]args){ArrayListmyList=newArrayList();string[]myArray;try{while(true){myList.add("MyString");}}catch(RuntimeExceptionre){System.out.println("CaughtaRuntimeException");}catch(Exceptione){system.out.println("CaughtanException");}System.out.println("Readytouse");}结果是什么?A)Executionterminatesinthefirstcatchstatement,andcaughtaRuntimeExceptionisprintedtotheconsole.B)Executionterminatesinthesecondcatchstatement,andcaughtanExceptionisprintedtotheconsole.C)Aruntimeerroristhrowninthethread"main".D)Executioncompletesnormally,andReadytouseisprintedtotheconsole.E)Thecodefailstocompilebecauseathrowskeywordisrequired.答案:C解析:[单选题]35.给定:System.out.println("5+2="+3+4);System.out.println("5+2="+(3+4));结果是什么?A)5+2=345+2=34B)5+2+3+45+2=7C)7=77+7D)5+2=345+2=7答案:D解析:[单选题]36.给定以下代码片段:Person.java:PublicclassPerson{Stringname;intage;PublicPerson(Stringn,inta){name=n;age=a;}PublicStringgetName()returnname;}PublicintgetAge(){returnage;}}Test.java:PublicstaticvoidcheckAge(List<Person>list,Predicate<Person>predicate){for(Personp:list){if(predicate.test(p)){Systen.out.print1n(+?");}}Publicstaticvoidmain(String[]args){List<Person>iList=Arrays.asList(newPerson("Hank",45),newPerson("Charlie",40),newPerson("Smith",38));//linen1}A)checkAge(iList,()->p.getAge()>40);B)checkAge(iList,Personp->p.getAge()>40);C)checkAge(iList,p->p.getAge()>40);D)checkAge(iList,(Personp)->{p.getAge()>40;});答案:C解析:[单选题]37.给定以下代码片段:publicstaticvoidmain(String[]args){String[][]arr={{"A.","B","C"},{"D","E"}};for(inti=0;i<arr.length;i++){for(intj=0;j<arr[i].length;j++){System.out.print(arr[i][j]+?");if(arr[i][j].equals("B")){break;}}continue;}}A)ABCB)ABCDEC)ABDED)Compilationfails.答案:C解析:[单选题]38.给定代码片段:PublicclassApp{Publicstaticvoidmain(String[]args){Stringstr1="Java";Stringstr2=newString("java");//linen1{System.out.println("Equal");}else{System.out.println("NotEqual");}}}Whichcodefragment,wheninsertedatlinen1,enablestheAppclasstoprintEqual?A)Stringstr3=str2;If(str1==str3)B)if(str1.equalsIgnoreCase(str2))C)Stringstr3=str2;If(str1.equals(str3))D)if(str1.toLowerCase()==str2.toLowerCase())答案:B解析:[单选题]39.Given:PublicclassSumTest{PublicstaticvoiddoSum(IntegerX,Integery){System.out.println("Integersumis?+(x+y));}PublicstaticvoiddoSur(doubleX,doubley){System.out.println("doublesumis?+(x+y));}PublicstaticvoiddoSum(floatX,floaty){System.out.println("floatsumis+(x+y));}PublicstaticvoiddoSum(intX,inty){System.out.println("intsumis?+(x+y));Publicstaticvoidmain(String[]args){DoSum(10,20);DoSum(10.0,20.0);Whatistheresult?A)intSuris30Floatsumis30.0B)intsuris30Doublesumis30C)Integersumis30Doublesumis30.0D)Integersumis30Floatsumis30.0答案:B解析:[单选题]40.Giventhecodefragment:String[]strs=newString[2];Intidx=0;For(StringS:strs){Strs[idx].concat("element?+idx);Idx++;For(idx=0;idx<strs.length;idx++){System.out.println(strs[idx]);Whatistheresult?eA)Element0Element1B)NullelementONullelement1C)NullNullD)ANulPointerExceptionisthrownatruntime.答案:D解析:[单选题]41.Given:ClassVehicle{Intx;Vehicle(){This(10);//linen1}Vehicle(intx){This.x=X;}}ClassCarextendsVehicle{Inty;Car(){Super();This(20);//linen2}Car(inty){This.y=y;}Publicstringtosuring(){Returnsuper.x+":?+this.y;}}Andgiventhecodefragment:Vehicley=newCar();System.out.println(y);Whatistheresult?A)10:20B)0:20C)Compilationfailsatlinen1D)Compilationfailsatlinen2答案:D解析:[单选题]42.构造函数调用必须是构造函数中的第一条语句,给定MySting类和Test类的定义:MyString.java:Packagep1;ClassMyString{Stringmsg;MyString(Stringmsg){This.msg=msg}}Test.java:Packagep1;PublicclassTest{Publicstaticvoidmain(String[]args){System.out.println("Hello"+newStringBuilder("javase.8"));System.out.println("Hello"+newMyString("javase.8"));}}Whatistheresult?A)HelloJavaSE8Hellop1.MyString@<<hashcodes>>B)HelloJavaSE8HelloJavaSE8C)Hellojava.lang.StringBuilder@<<hashcode1>>Hellop1.MyString@<<hashcode2>>D)ComplicationfailsattheTestclass答案:A解析:[单选题]43.Given:MainTest.java:PublicclassMainTest{Publicstaticvoidmain(int[]args){System.out.println("intmain?+args[0]);}Publicstaticvoidmain(object[]args){System.out.println("Objectmain?+args[0]);}Publicstaticvoidmain(String[]args){System.out.println("Stringmain?+args[0]);}}和命令:JavacMainTest.javaJavaMainTest123Whatistheresult?A)intmain1B)Objectmain1C)Stringmain1D)CompilationfailsE)Anexceptionisthrownatruntime答案:C解析:[单选题]44.鉴于代码片段:Intnum[][]=newint[1][3];For(inti=0;i<num.length;i++){For(intj=0;j<num[i].length;j++){Num[i][j]=10;}}哪个选项代表外循环成功完成后num数组的状态?A)num[0][0]=10Num[0][1]=10Num[0][2]=10B)num[0][0]=10Num[1][0]=10Num[2][0]=10C)num[0][0]=10Num[0][1]=0Num[0][2]=0D)num[0][0]=10Num[0][1]=10Num[0][2]=10Num[0][3]=10Num[1][0]=0Num[1][1]=0Num[1][2]=0Num[1][3]=0答案:A解析:[单选题]45.鉴于代码片段:PublicclassPerson{Stringname;Intage=25;}PublicPerson(Stringname){This();//linen1SetName(name);}PublicPerson(Stringname,intage){Person(name);//linen2SetAge(age);}//setterandgettermethodsgoherePublicStringshow(){Returnname+??+age+??+number;}Publicstaticvoidmain(String[]args){Personp1=newPerson("Jesse");Personp2=newPerson("Walter",52);System.out.println(p1.show());System.out.println(p2.show());}}结果是什么?A)Jesse25Walter52B)Compilationfailsonlyatlinen1C)Compilationfailsonlyatlinen2D)Compilationfailsatbothlinen1andlinen2答案:D解析:[单选题]46.给定以下代码用于Planet对象:PublicclassPlanet{PublicStringname;Publicintmoons;PublicPlanet(Stringnamerintmoons){This.name=name;.This.moons=moons;}}Andthefollowingmainmethod:Publicstaticvoidmain(String[]args){Planet[]planets={NewPlanet("Mercury",0),NewPlanet("Venus",0),NewPlanet("Earth",1),NewPlanet("Mars",2)};System.out.println(planets);System.out.println(planets[2]);System.out.println(planets[2].moons);输出是什么?A)planetsEarth1B)[LPlanets.Planet;@15db9742Earth1C)[LPlanets.Planet;015db9742Planets.Planet@6d06d69c1D)[LPlanets.Planet;@15db9742Planets.Planet@6d06d69c[LPlanets.Moon;@7852e922E)[LPlanets.Planet;@15db9742Venus0答案:C解析:[单选题]47.你被要求为一个购物应用程序开发一个程序,你会得到以下信息:Toy类的哪个定义为类层次结构添加了一个有效的抽象层?A)publicabstractclassToy{PublicabstractintcalculatePrice(Toyt);PublicvoidprintToy(Toyt){codeGoeshere*/}B)publicabstractclassToy{PublicintcalculatePrice(Toyt);PublicvoidprintToy(Toyt);}C)publicabstractclassToy{PublicintcalculatePrice(Toyt);PublicfinalvoidprintToy(Toyt){codegoeshere*/}D)publicabstractclassToy{PublicabstractintcalculatePrice(Toyt){codegoeshere*/}PublicabstractvoidprintToy(Toyt){codegoeshere*/}答案:A解析:[单选题]48.Giventhefollowingcode:Int[]intArr={15,30,45,60,75};IntArr[2]=intArr[4];IntArr[4]=90;WhatarethevaluesofeachelementinintArrafterthiscodehasexecuted?A)15,60,45,90,75B)15,90,45,90,75C)15,30,75,60,90D)15,30,90,60,90E)15,4,45,60,90答案:C解析:[单选题]49.Giventhecontentofthreefiles:Whichstatementistrue?`A)OnlytheAJavafilecompilessuccessfully.B)OnlytheBjavafilecompilessuccessfully.C)OnlytheCjavafilecompilessuccessfully.D)TheAJavaandBjavafilescompilesuccessfully.E)TheBjavaandCjavafilescompilesuccessfully.F)TheAJavaandCjavafilescompilesuccessfully.答案:A解析:[单选题]50.Given:PublicclassTestscope{Publicstaticvoidmain(string[]args){Intvar1=200;System.out.print(doCalc(var1));System.out.print(""+var1);}StaticintdoCalc(intvar1){Var1=var1*2;Returnvar1;}Whatistheresult?A)400200B)200200C)400400D)Compilationfails答案:A解析:[单选题]51.Giventhefollowingclassdeclarations:Which答案:failstocompile?A)OptionAB)OptionBC)OptionCD)OptionDE)OptionE答案:D解析:[单选题]52.WhichstatementistrueaboutJavabytecode?A)Itcanrunonanyplatform.B)Itcanrunonanyplatformonlyifitwascompiledforthatplatform.C)ItcanrunonanyplatformthathastheJavaRuntimeEnvironment.D)ItcanrunonanyplatformthathasaJavacompiler.E)ItcanrunonanyplatformonlyifthatplatformhasboththeJavaRuntimeEnvironmentandaJavacompiler.答案:C解析:[单选题]53.Given:PublicclassMarkList{intnum;publicstaticvoidgraceMarks(MarkListobj4){obj4.num+=10;}publicstaticvoidmain(String[]args){MarkListobj1=newMarkList();MarkListobj2=obj1;MarkListobj3=null;Obj2.num=60;graceMarks(obj2);}}HowmanyMarkListinstancesarecreatedinmemoryatruntime?A)1B)2C)3D)4答案:A解析:[单选题]54.Given:PublicclassTriangle{Staticdoublearea;intb=2,h=3;Publicstaticvoidmain(string[]args){Doublep,B,h;//linen1If(area==0){B=3;H=4;P=0.5;}Area=p*b*h;//linen2System.out.println("Areais"+area);}Whatistheresult?A)Areais6.0B)Areais3.0C)Compilationfailsatline1D)Compilationfailsatline2答案:D解析:[单选题]55.Given:PublicclassAPP{publicstaticvoidmian(String[]args){Boolean[]bool=newBoolean[2];bool[0]=newBoolean(Boolean.parseBoolean("true"));bool[1]=newBoolean(null);System.out.println(bool[0]+""+bool[1]);}}Whatistheresult?A)truefalseB)truenullC)CompilationfailsD)ANullPointerExceptionisthrownatruntime答案:A解析:[单选题]56.GiventhefollowingcodefortheclassesMyExceptionandTest:PublicclassMyExceptionextendsRuntimeException{}PublicclassTest{Publicstaticvoidmain(String[]args){Try{Method1();}Catch(MyExceptionne){System.out.print("A");}}Publicstaticvoidmethod1(){//linen1Try{ThrowMath.random()>0.5?newMyException():newRuntimeException();}Catch(RuntimeExceptionre){System.out.print("B");}}}Whatistheresult?A)AB)BC)EitherAorBD)ABE)Acompiletimeerroroccursatlinen1答案:B解析:[单选题]57.GivenPublicclassApp{StringmyStr="9009";publicvoiddostuff(stringstr){intmyNum=0;try{Stringmystr=str;myNum=Integer.parseInt(myStr);}catch(NumberFormatExceptionne){System.err.println("Error");}System.out.println("mystr:"+myStr+",myNum:"+myNum);}publicstaticvoidmain(String[]args){Appobj=newApp();obj.doStuff("7007");}}Whatistheresult?A)ErrorB)myStr:7007,myNum:7007C)myStr:9009,myNum:7007D)myStr:7007,myNum:9009答案:C解析:[单选题]58.Giventhecodefragment:Intnums1[]=newint[3];Intnums2[]={1,2,3,4,5};Nums1=nums2;For(intx:nums1){System.out.print(x+":");}Whatistheresult?A)1:2:3:4:5:B)1:2:3:C)Compilationfails.D)AnArrayoutofBoundsExceptionisthrownatruntime.答案:A解析:[单选题]59.Given:PublicclassProduct{Intid;Stringname;PublicProduct(intid,stringname){This.id=id;T=name;}}Andgiventhecodefragment:4\Productp1=newProduct(101,"Pen");5\Productp2=newProduct(101,"Pen");6\Productp3=pl;7\booleanans1=pl==p2;8\booleanans2=.equals();9\system.out.print(ans1+":"+ans2);Whatistheresult?A)true:trueB)true:falseC)false:trueD)false:false答案:C解析:[单选题]60.WhichoneofthefollowingcodeexamplesusesvalidJavasyntax?A)OptionAB)OptionBC)OptionCD)OptionD答案:A解析:[单选题]61.Giventhecodefragment:Intn[][]={{1,3},{2,4}};For(inti=n.length-1;i>=0;i--){For(inty:n[i]){System.out.print(y);}}Whatistheresult?A)1324B)2413C)3142D)4231答案:B解析:[单选题]62.Given:Whatistheresult?A)Anexceptionisthrownatruntime.B)InitializedStartedInitializedC)InitializedStartedD)Compilationfails.答案:D解析:[单选题]63.Giventhecodefragment:Publicstaticvoidmain(String[]args){Try{Intnum=10;Intdiv=0;Intans=nim/div;}catch(ArithmeticExeptionae){Ans=0//linen1}catch(Exceptione){System.out.println("Invalidcalculation");}System,out.println("答案:="+ans);//linen2}Whatistheresult?A)答案:=0B)InvalidcalculationC)Compilationfailsonlyatlinen1.D)Compilationfailsonlyatlinen2.E)Compilationfailsonlyatlinen1andline2.答案:E解析:[单选题]64.Given:PublicclassMyField{Intx;Inty;PublicvoiddoStuff(intx,inty){This.x=x;Y=this.y;}Publicvoiddisplay(){System.out.print(x+""+y+":");}Publicstaticvoidmain(String[]args){MyFieldm1=newMyField();M1.x=100;M1.y=200;MyFieldm2=newMyField();M2.doStuff(m1.x,m1.y);M1.display();M2.display();}}Whatistheresult?A)1000:100200:B)1000:1000:C)100200:100200:D)100200:1000:答案:D解析:[单选题]65.Given:PublicclassVowel{Privatecharvar;Publicstaticvoidmain(String[]args){Charvar1='a';Charvar2=var1;Var2='e';Vowelobj1=newVowel();Vowelobj2=obj1;Obj1.var='i';Obj2.var='o';System.out.println(var1+","+var2);System.out.print(obj1.var+","+obj2.var);}}Whatistheresult?A)E,ei,oB)A,ei,oC)A,eo,oD)E,eo,o答案:C解析:[单选题]66.Giventhecodefragment:If(aVal++<10){System.out.println(aVal+"HelloUniverse!");}else{System.out.println(aVal+"HelloWord!");}WhatistheresultiftheintegeraVaris9?A)Compilationfails.B)10HelloUniverse!C)10HelloWorld!D)9HelloWorld!答案:B解析:[单选题]67.Given:PublicclassMyClass{Publicstaticvoidmain(String[]args){Strings="JavaDuke";Intlen=s.trim().length();System.out.print(len);}}Whatistheresult?A)Compilationfails.B)11C)8D)9E)10答案:D解析:[单选题]68.Given:PublicclassTest{Publicstaticvoidmain(String[]args){Booleana=newBoolean(Boolean.valueOf(args[0]));Booleanb=newBoolean(args[1]);System.out.println(a+""+b);}}Andgiventhecomman