Java期末练习卷附答案

Java期末练习卷附答案单选题（总共40题）1.单选题Theoutputfromthefollowingcodeis__________.()

Java.util.ArrayList<String>list=newjava.util.ArrayList<String>();

List.add("NewYork");

Java.util.ArrayList<String>list1=list;

List.add("Atlanta");

List1.add("Dallas");

System.out.println(list1);(1分)A、[NewYork]B、[NewYork,Atlanta]C、[NewYork,Atlanta,Dallas]D、[NewYork,Dallas]答案：C解析：

暂无解析2.单选题Theaverage-timecomplexityformergesortis_________.()(1分)A、O(1)B、O(logn)C、O(n)D、O(nlogn)E、O(n*n)答案：D解析：

暂无解析3.单选题Amethodthatisassociatedwithanindividualobjectiscalled__________.()(1分)A、astaticmethodB、aclassmethodC、aninstancemethodD、anobjectmethod答案：C解析：

暂无解析4.单选题WhichofthefollowingareJavakeywords?()(1分)A、instanceOfB、instanceofC、castD、casting答案：B解析：

暂无解析5.单选题Whichmethoddoyouusetotestifanelementisinasetorlistnamedx?()(1分)A、(elementinstanceofList)||(elementinstanceofSet)B、x.in(element)C、x.contain(element)D、x.contains(element)E、x.include(element)答案：D解析：

暂无解析6.单选题Whatistheoutputofthefollowingcode?()

PublicclassTest{

Publicstaticvoidmain(String[]args){

Strings1=newString("WelcometoJava!");

Strings2=newString("WelcometoJava!");

If(s1==s2)

System.out.println("s1ands2referencetothesameStringobject");

Else

System.out.println("s1ands2referencetodifferentStringobjects");

}

}(1分)A、s1ands2referencetothesameStringobjectB、s1ands2referencetodifferentStringobjects答案：B解析：

暂无解析7.单选题SupposeList<String>list=newArrayList<String>.Whichofthefollowingoperationsarecorrect?()(1分)A、list.add("Red");B、list.add(newInteger(100));C、list.add(newjava.util.Date());D、list.add(newArrayList());答案：A解析：

暂无解析8.单选题Does<?superNumber>representasuperclassofNumber?()(1分)A、YesB、No答案：A解析：

暂无解析9.单选题HowmanytimesistherecursivemoveDisksmethodinvokedfor3disks?()(1分)A、3B、7C、10D、14答案：B解析：

暂无解析10.单选题Theworst-timecomplexityforinsertionsortis_____________.()(1分)A、O(1)B、O(logn)C、O(n)D、O(nlogn)E、O(n*n)答案：E解析：

暂无解析11.单选题ToemptyaCollectionoraMap,youusethe__________method.()(1分)A、emptyB、clearC、zeroD、setEmpty答案：B解析：

暂无解析12.单选题Whatisoutputofthefollowingcode:()

PublicclassTest{

Publicstaticvoidmain(String[]args){

Int[]x={120,200,016};

For(inti=0;i<x.length;i++)

System.out.print(x[i]+"");

}

}(1分)A、12020016B、12020014C、12020020D、016isacompileerror.Itshouldbewrittenas16.答案：B解析：

暂无解析13.单选题Tofindamaximumobjectinanarrayofstrings()g点,String[]names={"red","green","blue"}),use(D)(1分)A、Arrays.max(names)B、Arrays.sort(names)C、Collections.max(names)D、Collections.max(Arrays.asList(names))E、Noneoftheabove答案：E解析：

暂无解析14.单选题________isinvokedtocreateanobject.()(1分)A、AconstructorB、ThemainmethodC、AmethodwithareturntypeD、Amethodwiththevoidreturntype答案：A解析：

暂无解析15.单选题___________isattachedtotheclassofthecomposingclasstodenotetheaggregationrelationshipwiththecomposedobject.()(1分)A、AnemptydiamondB、AsoliddiamondC、AnemptyovalD、Asolidoval答案：A解析：

暂无解析16.单选题Fillinthecodetocompletethefollowingmethodforsortingalist.()

Publicstaticvoidsort(double[]list){

___________________________;

}

Publicstaticvoidsort(double[]list,inthigh){

If(high>1){

//Findthelargestnumberanditsindex

IntindexOfMax=0;

Doublemax=list[0];

For(inti=1;i<=high;i++){

If(list[i]>max){

Max=list[i];

IndexOfMax=i;

}

}

//Swapthelargestwiththelastnumberinthelist

List[indexOfMax]=list[high];

List[high]=max;

//Sorttheremaininglist

Sort(list,high-1);

}

}(1分)A、sort(list)B、sort(list,list.length)C、sort(list,list.length-1)D、sort(list,list.length-2)答案：C解析：

暂无解析17.单选题Whichofthefollowingiscorrecttosorttheelementsinalistlst?()(1分)A、lst.sort()B、Collections.sort(lst)C、Arrays.sort(lst)D、newLinkedList<String>(newString[]{"red","green","blue"})答案：B解析：

暂无解析18.单选题Analyzingalgorithmefficiencyis________.()(1分)A、tomeasuretheiractualexecutiontimeB、toestimatetheirexecutiontimeC、toestimatetheirgrowthfunction答案：C解析：

暂无解析19.单选题Whatis1+1+1+1+1==5?()(1分)A、trueB、falseC、Thereisnoguaranteethat1+1+1+1+1==5istrue.答案：A解析：

暂无解析20.单选题Theworst-timecomplexityforheapsortis_________()(1分)A、O(1)B、O(logn)C、O(n)D、O(nlogn)E、O(n*n)答案：D解析：

暂无解析21.单选题Thetimecomplexityfortheselectionsortalgorithminthetextis________.()(1分)A、O(nlogn)B、O(n^2)C、O(logn)D、O(2^n)答案：B解析：

暂无解析22.单选题Analyzethefollowingcode:()

PublicclassTest{

Publicstaticvoidmain(Stringargs[]){

NClassnc=newNClass();

Nc点t=nc点t++;

}

}

ClassNClass{

Intt;

PrivateNClass(){

}

}(1分)A、TheprogramhasacompileerrorbecausetheNClassclasshasaprivateconstructor.B、Theprogramdoesnotcompilebecausetheparameterlistofthemainmethodiswrong.C、Theprogramcompiles,buthasaruntimeerrorbecausethasnoinitialvalue.D、Theprogramcompilesandrunsfine.答案：A解析：

暂无解析23.单选题WhichofthedatatypesbelowcouldbeusedtostoreelementsintheirnaturalorderbasedonthecompareTomethod?()(1分)A、HashSetB、TreeSetC、LinkedHashSetD、CollectionE、Set答案：B解析：

暂无解析24.单选题SupposethexMethod()isinvokedfromamainmethodinaclassasfollows,xMethod()is_________intheclass.()

Publicstaticvoidmain(String[]args){

XMethod();

}(1分)A、astaticmethodB、aninstancemethodC、astaticmethodoraninstancemethod答案：A解析：

暂无解析25.单选题Whichofthefollowingstatementsispreferredtocreateastring"WelcometoJava"?()(1分)A、Strings="WelcometoJava";B、Strings=newString("WelcometoJava");C、Strings;s="WelcometoJava";D、Strings;s=newString("WelcometoJava");答案：A解析：

暂无解析26.单选题Analyzethefollowingcode.()

ClassTest{

Publicstaticvoidmain(String[]args){

Strings;

System.out.println("sis"+s);

}

}(1分)A、Theprogramhasacompileerrorbecausesisnotinitialized,butitisreferencedintheprintlnstatement.B、Theprogramhasaruntimeerrorbecausesisnotinitialized,butitisreferencedintheprintlnstatement.C、Theprogramhasaruntimeerrorbecausesisnullintheprintlnstatement.D、Theprogramcompilesandrunsfine.答案：A解析：

暂无解析27.单选题Whatistheoutputofthefollowingcode?()

ArrayList<Integer>list=newArrayList<>();

List.add(1);

List.add(2);

List.add(3);

List.remove(2);

System.out.println(list);(1分)A、[1,2,3]B、[1,2]C、[1]D、[1,3]E、[2,3]答案：B解析：

暂无解析28.单选题SupposeTestSimpleCircleandSimpleCircleinListing9.1areintwoseparatefilesnamedTestSimpleCircle.javaandSimpleCircle.java,respectively.WhatistheoutcomeofcompilingTestsimpleCircle.javaandthenSimpleCircle.java?()(1分)A、OnlyTestSimpleCircle.javacompiles.B、OnlySimpleCircle.javacompiles.C、Bothcompilefine.D、Neithercompilessuccessfully.答案：C解析：

暂无解析29.单选题Therelationshipbetweenaninterfaceandtheclassthatimplementsitis()(1分)A、CompositionB、AggregationC、InheritanceD、None答案：C解析：

暂无解析30.单选题Analyzethefollowingcode.Whichofthefollowingstatementsiscorrect?()

PublicclassTest{

Publicstaticvoidmain(String[]args){

Numberx=newInteger(3);

System.out.println(Value());

System.out.println((Integer)pareTo(newInteger(4)));

}

}(1分)A、TheprogramhasacompileerrorbecauseanIntegerinstancecannotbeassignedtoaNumbervariable.B、TheprogramhasacompileerrorbecauseintValueisanabstractmethodinNumber.C、TheprogramhasacompileerrorbecausexcannotbecastintoInteger.D、Theprogramhasacompileerrorbecausethememberaccessoperator(.)isexecutedbeforethecastingoperator.E、Theprogramcompilesandrunsfine.答案：D解析：

暂无解析31.单选题Analyzethefollowingcode.()

Importjava.util.*;

PublicclassTest{

Publicstaticvoidmain(String[]args)throwsException{

TreeSet<String>set=newTreeSet<>();

Set.add("Red");

Set.add("Yellow");

Set.add("Green");

Set.add("Blue");

SortedSettemp=set.headSet("Purple");

System.out.println(temp.first());

}

}(1分)A、TheprogramdisplaysRedB、TheprogramdisplaysBlueC、TheprogramdisplaysGreenD、TheprogramdisplaysYellowE、TheprogramdisplaysPurple答案：B解析：

暂无解析32.单选题ThetimecomplexityfortheTowersofHonoialgorithminthetextis________.()(1分)A、O(n)B、O(n^2)C、O(n^3)D、O(2^n)答案：D解析：

暂无解析33.单选题WhichofthefollowingdeclaresanabstractmethodinanabstractJavaclass?()(1分)A、publicabstractmethod();B、publicabstractvoidmethod();C、publicvoidabstractmethod();D、publicvoidmethod(){}E、publicabstractvoidmethod(){}答案：B解析：

暂无解析34.单选题ThetimecomplexityfortheSieveofEratosthenesalgorithmis________.()(1分)A、O(n)B、O(n^(1.5)/logn)C、O(logn)D、O(2^n)答案：B解析：

暂无解析35.单选题Whatistheoutputofthefollowingcode?()

Importjava.util.*;

PublicclassTest{

Publicstaticvoidmain(String[]args){

List<String>list1=newArrayList<>();

List1.add("Atlanta");

List1.add("Macon");

List1.add("Savanna");

List<String>list2=newArrayList<>();

List2.add("Atlanta");

List2.add("Macon");

List2.add("Savanna");

List<String>list3=newArrayList<>();

List3.add("Macon");

List3.add("Savanna");

List3.add("Atlanta");

System.out.println(list1.equals(list2)+""+list1.equals(list3));

}

}(1分)A、truetrueB、truefalseC、falsefalseD、falsetrue答案：B解析：

暂无解析36.单选题Whatislistafterthefollowingcodeisexecuted?()

ArrayList<Integer>list=newArrayList<>();

List.add(1);

List.add(2);

List.add(3);

List.add(4);

List.add(5);

List.remove(2);

System.out.println(list);(1分)A、[1,2,3,4,5]B、[2,3,4,5]C、[1,3,4,5]D、[1,2,4,5]E、[1,2,3,4]答案：D解析：

暂无解析37.单选题Whatisthenumberofiterationsinthefollowingloop:()

Intcount=5;

While(count<n){

Count=count+3;

}(1分)A、n-5B、n-3C、n/3-1D、(n-5)/3E、theceilingof(n-5)/3答案：E解析：

暂无解析38.TodeclareaclassnamedAwithagenerictype,use(1分)A、publicclassA<E>{...}B、publicclassA<E,F>{...}C、publicclassA<E,F>{...}D、publicclassA(E,F){...}答案：A解析：

暂无解析39.单选题__________representsanentityintherealworldthatcanbedistinctlyidentified.()(1分)A、AclassB、AnobjectC、AmethodD、Adatafield答案：B解析：

暂无解析40.单选题ThetimecomplexityfortheTowersofHonoialgorithminthetextis________.()(1分)A、O(n)B、O(n^2)C、O(n^3)D、O(2^n)答案：D解析：

暂无解析多选题（总共40题）1.多选题Whichofthefollowingstatementsaretrue?()(1分)A、Everyrecursivemethodmusthaveabasecaseorastoppingcondition.B、Everyrecursivecallreducestheoriginalproblem,bringingitincreasinglyclosertoabasecaseuntilitbecomesthatcase.C、Infiniterecursioncanoccurifrecursiondoesnotreducetheprobleminamannerthatallowsittoeventuallyconvergeintothebasecase.D、Everyrecursivemethodmusthaveareturnvalue.E、Arecursivemethodisinvokeddifferentlyfromanon-recursivemethod.答案：ABC解析：

暂无解析2.多选题Giventhefollowingcode,findthecompileerror.()

PublicclassTest{

Publicstaticvoidmain(String[]args){

M(newGraduateStudent());

M(newStudent());

M(newPerson());

M(newObject());

}

Publicstaticvoidm(Studentx){

System.out.println(x.toString());

}

}

ClassGraduateStudentextendsStudent{

}

ClassStudentextendsPerson{

@Override

PublicStringtoString(){

Return"Student";

}

}

ClassPersonextendsObject{

@Override

PublicStringtoString(){

Return"Person";

}

}(1分)A、m(newGraduateStudent())causesanerrorB、m(newStudent())causesanerrorC、m(newPerson())causesanerrorD、m(newObject())causesanerror答案：CD解析：

暂无解析3.多选题SupposeArrayListxcontainstwostrings[Beijing,Singapore].Whichofthefollowingmethodwillcauseruntimeerrors?()(1分)A、x.get(1)B、x.set(2,"NewYork");C、x.get(2)D、x.remove(2)E、x.size()答案：BCD解析：

暂无解析4.多选题SupposeAisanabstractclass,Bisaconcretesubclassof

A,andbothAandBhaveano-argconstructor.Whichofthefollowingiscorrect?()(1分)A、Aa=newA();B、Aa=newB();C、Bb=newA();D、Bb=newB();答案：BD解析：

暂无解析5.多选题Whichofthefollowingstatementsaretrue?()(1分)A、AnArrayListcangrowautomatically.B、AnArrayListcanshrinkautomatically.C、YoucanreducethecapacityofanArrayListbyinvokingthetrimToSize()methodonthelist.D、YoucanreducethecapacityofaLinkedListbyinvokingthetrimToSize()methodonthelist.答案：AC解析：

暂无解析6.多选题SupposeArrayListxcontainsthreestrings[Beijing,Singapore,Tokyo].Whichofthefollowingmethodswillcauseruntimeerrors?()(1分)A、x.get(2)B、x.set(3,"NewYork");C、x.get(3)D、x.remove(3)E、x.size()答案：BCD解析：

暂无解析7.多选题Whichofthefollowingstatementsaretrue?()(1分)A、Generictypeinformationispresentatcompiletime.B、Generictypeinformationisnotpresentatruntime.C、Youcannotcreateaninstanceusingagenericclasstypeparameter.D、Youcannotcreateanarrayusingagenericclasstypeparameter.E、Youcannotcreateanarrayusingagenericclass.答案：ABCDE解析：

暂无解析8.多选题WhichofthefollowingmethodsareintheCollectioninterface?()(1分)A、remove(o:Object):booleanB、removeAll(c:Collection<?>):booleanC、delete(o:D、:booleanE、deleteAll(c:Collection<?>):boolean答案：AB解析：

暂无解析9.多选题Whichofthefollowingstatementsiscorrect?()(1分)A、Comparable<String>c=newString("abc");B、Comparable<String>c="abc";C、Comparable<String>c=newDate();D、Comparable<Object>c=newDate();答案：AB解析：

暂无解析10.多选题Giventhefollowingcode,findthecompileerror.()

PublicclassTest{

Publicstaticvoidmain(String[]args){

M(newGraduateStudent());

M(newStudent());

M(newPerson());

M(newObject());

}

Publicstaticvoidm(Studentx){

System.out.println(x.toString());

}

}

ClassGraduateStudentextendsStudent{

}

ClassStudentextendsPerson{

@Override

PublicStringtoString(){

Return"Student";

}

}

ClassPersonextendsObject{

@Override

PublicStringtoString(){

Return"Person";

}

}(1分)A、m(newGraduateStudent())causesanerrorB、m(newStudent())causesanerrorC、m(newPerson())causesanerrorD、m(newObject())causesanerror答案：CD解析：

暂无解析11.多选题SupposeListlist=newArrayList().Whichofthefollowingoperationsarecorrect?()(1分)A、list.add("Red");B、list.add(newInteger(100));C、list.add(newjava.util.Date());D、list.add(newArrayList());答案：ABCD解析：

暂无解析12.多选题WhenyoucreateanArrayListusingArrayList<String>x=newArrayList<>(2),________()(1分)A、twoelementsarecreatedinthearraylist.B、noelementsarecurrentlyinthearraylist.C、thearraylistsizeiscurrently2.D、thearraylistcapacityiscurrently2.答案：BD解析：

暂无解析13.多选题WhichofthefollowingcanbeusedtoreplaceYYYYYYYYinthefollowingcode?()

PublicclassWildCardDemo3{

Publicstaticvoidmain(String[]args){

GenericStack<String>stack1=newGenericStack<>();

GenericStack<Object>stack2=newGenericStack<>();

Stack2.push("Java");

Stack2.push(2);

Stack1.push("Sun");

Add(stack1,stack2);

WildCardDemo2.print(stack2);

}

Publicstatic<T>voidYYYYYYYY{

While(!stack1.isEmpty())

Stack2.push(stack1.pop());

}

}(1分)A、add(GenericStack<T>stack1,GenericStack<T>stack2)B、add(GenericStack<?extendsT>stack1,GenericStack<T>stack2)C、add(GenericStack<T>stack1,GenericStack<?superT>stack2)D、add(GenericStack<T>stack1,GenericStack<Object>stack2)答案：BC解析：

暂无解析14.多选题Whichofthefollowingstatementsistrue?()(1分)A、Youcanalwayspassaninstanceofasubclasstoaparameterofitssuperclasstype.Thisfeatureisknownaspolymorphism.B、Thecompilerfindsamatchingmethodaccordingtoparametertype,numberofparameters,andorderoftheparametersatcompiletime.C、Amethodmaybeimplementedinseveralsubclasses.TheJavaVirtualMachinedynamicallybindstheimplementationofthemethodatruntime.D、Dynamicbindingcanapplytostaticmethods.E、Dynamicbindingcanapplytoinstancemethods.答案：ABCE解析：

暂无解析15.多选题SupposeArrayList<Double>list=newArrayList<>().Whichofthefollowingstatementsarecorrect?()(1分)A、list.add(5.5);//5.5isautomaticallyconvertedtonewDouble(5.5)B、list.add(3.0);//3.0isautomaticallyconvertedtonewDouble(3.0)C、DoubledoubleObject=list.get(0);//NocastingisneededD、doubled=list.get(1);//Automaticallyconvertedtodouble答案：ABCD解析：

暂无解析16.多选题WhichofthefollowingcanbeusedtoreplaceYYYYYYYYinthefollowingcode?()

PublicclassWildCardDemo3{

Publicstaticvoidmain(String[]args){

GenericStack<String>stack1=newGenericStack<>();

GenericStack<Object>stack2=newGenericStack<>();

Stack2.push("Java");

Stack2.push(2);

Stack1.push("Sun");

Add(stack1,stack2);

WildCardDemo2.print(stack2);

}

Publicstatic<T>voidYYYYYYYY{

While(!stack1.isEmpty())

Stack2.push(stack1.pop());

}

}(1分)A、add(GenericStack<T>stack1,GenericStack<T>stack2)B、add(GenericStack<?extendsT>stack1,GenericStack<T>stack2)C、add(GenericStack<T>stack1,GenericStack<?superT>stack2)D、add(GenericStack<T>stack1,GenericStack<Object>stack2)答案：BC解析：

暂无解析17.多选题Supposes1ands2aretwostrings.Whichofthefollowingstatementsorexpressionsareincorrect?()(1分)A、Strings=newString("newstring");B、Strings3=s1+s2C、s1>=s2D、inti=s1.lengthE、s1.charAt(0)='5'答案：CDE解析：

暂无解析18.多选题Whichofthefollowingstatementsiscorrect?()(1分)A、Genericscanhelpdetecttypeerrorsatcompiletime,thusmakeprogramsmorerobust.B、Genericscanmakeprogramseasytoread.C、Genericscanavoidcumbersomecastings.D、Genericscanmakeprogramsrunfaster.答案：ABC解析：

暂无解析19.多选题WhichofthefollowingisapossibleoutputfrominvokingMath.random()?()(1分)A、3.43B、0.5C、0.0D、1.0答案：BC解析：

暂无解析20.多选题Whichofthefollowingstatementswillconvertastringsintoiofinttype?()(1分)A、i=Integer.parseInt(s);B、i=(newInteger(s)).intValue();C、i=Integer.valueOf(s).intValue();D、i=Integer.valueOf(s);E、i=(int)(Double)parseDouble(s));答案：ABCDE解析：

暂无解析21.多选题java.util.Stackisasubclassof__________.()(1分)A、java.util.ArrayListB、java.util.LinkedListC、java.util.AbstractListD、java.util.VectorE、java.util.List答案：CDE解析：

暂无解析22.多选题Tocheckifastringscontainstheprefix"Java",youmaywrite()(1分)A、if(s.startsWith("Java"))...B、if(s.indexOf("Java")==0)...C、if(s.substring(0,4).equals("Java"))...D、if(s.charAt(0)=='J'&&s.charAt(1)=='a'&&s.charAt(2)=='v'&&s.charAt(3)=='a')...答案：ABCD解析：

暂无解析23.多选题Whichofthefollowingstatementsaretrue?()(1分)A、java.util.Listinheritsallthemethodsfromjava.util.Collection.Additionally,itcontainsnewmethodsformanipulatingalist.B、TheAbstractListclassprovidesapartialimplementationfortheListinterface.C、ArrayListisaconcreteimplementationofListusinganarray.D、LinkedListisaconcreteimplementationofListusingalinkedlist.LinkedListcontainsallthemethodsinListandadditionalnewmethodsformanipulatingalinkedlist.E、ListIteratorisasubinterfaceofIteratoranditprovidesthemethodstosupportbi-directionaltraversalofalist.答案：ABCDE解析：

暂无解析24.多选题FillinthecodetocompletethefollowingmethodforcomputingaFibonaccinumber.()

Publicstaticlongfib(longindex){

If(index==0)//Basecase

Return0;

Elseif(index==1)//Basecase

Return1;

Else//Reductionandrecursivecalls

Return__________________;

}(1分)A、fib(index-1)B、fib(index-2)C、fib(index-1)+fib(index-2)D、fib(index-2)+fib(index-1)答案：CD解析：

暂无解析25.多选题TheCollectioninterfaceisthebaseinterfacefor_____________.()(1分)A、SetB、ListC、ArrayListD、LinkedListE、Map答案：ABCD解析：

暂无解析26.多选题Analyzethefollowingcode:()

Importjava.util.*;

PublicclassTest{

Publicstaticvoidmain(String[]args){

HashSet<String>set1=newHashSet<>();

Set1.add("red");

Set<String>set2=set1.clone();

}

}(1分)A、Line5iswrongbecauseaHashSetobjectcannotbecloned.B、Line5hasacompileerrorbecauseset1.clone()returnsanObject.YouhavetocastittoSetinordertocompileit.C、Theprogramwillbefineifset1.clone()isreplacedby(Set<String>)set1.clone()D、Theprogramwillbefineifset1.clone()isreplacedby(Set<String>)(set1.clone())E、Theprogramwillbefineifset1.clone()isreplacedby(HashSet<String>)(set1.clone())答案：BDE解析：

暂无解析27.多选题Whichofthefollowingareincorrect?()(1分)A、Anabstractclasscontainsconstructors.B、Theconstructorsinanabstractclassshouldbeprotected.C、Theconstructorsinanabstractclassareprivate.D、Youmaydeclareafinalabstractclass.E、Aninterfacemaycontainconstructors.答案：CDE解析：

暂无解析28.多选题Whichofthefollowingdatatypeshaveiterators?()(1分)A、HashSetB、TreeSetC、ArrayListD、LinkedListE、LinkedHashSet答案：ABCDE解析：

暂无解析29.多选题Theelementsin________aresorted.()(1分)A、TreeSetB、ListC、TreeMapD、HashSetE、LinkedHashSet答案：AC解析：

暂无解析30.Whichofthefollowingstatementsregardingabstractmethodsistrue?()(1分)A、Abstractclasseshaveconstructors.B、Aclassthatcontainsabstractmethodsmustbeabstract.C、Itispossibletodeclareanabstractclassthatcontainsnoabstractmethods.D、Anabstractmethodcannotbecontainedinanonabstractclass.E、Adatafieldcanbedeclaredabstract.答案：ABCD解析：

暂无解析31.多选题Whichofthefollowingis/arecorrect?()(1分)A、Aconstructormaybestatic.B、Aconstructormaybeprivate.C、Aconstructormayinvokeastaticmethod.D、Aconstructormayinvokeanoverloadedconstructor.E、Aconstructorinvokesitssuperclassno-argconstructorbydefaultifaconstructordoesnotinvokeanoverloadedconstructororitssuperclassconstructor.答案：BCDE解析：

暂无解析32.多选题Whichofthefollowingdatatypeshaveiterators?()(1分)A、HashSetB、TreeSetC、ArrayListD、LinkedListE、LinkedHashSet答案：ABCDE解析：

暂无解析33.多选题Analyzethefollowingcode:()

ClassTest{

Privatedoublei;

PublicTest(do