大数据基础技能试题及答案.docx
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大数据基础技能试题及答案
Java基础
1.Whichofthefollowingwillcompilecorrectly?
A）floatf=10f;
B）floatf=10.1;
C）floatf=10.1f;
D）byteb=10b;
2.Whichdeclarationsofidentifiersarelegal
A.$persons
B.TwoUsers
C.*point
D.this
E._endline
3.Whichstatementofassigningalongtypevariabletoahexadecimalvalueiscorrect
A.longnumber=345L;
B.longnumber=0345;
C.longnumber=0345L;
D.longnumber=0x345L
4.Whichofthefollowingfragmentsmightcauseerrors
A.Strings="Gonewiththewind";
Stringt="good";
Stringk=s+t;
B.Strings="Gonewiththewind";
Stringt;
t=s[3]+"one";
C.Strings="Gonewiththewind";
Stringstandard=s.toUpperCase（）;
D.Strings="homedirectory";
Stringt=s-"directory";
5.Whicharesyntacticallyvalidstatementat//pointx
classPerson{
privateinta;
publicintchange（intm）{returnm;}
}
publicclassTeacherextendsPerson{
publicintb;
publicstaticvoidmain（Stringarg[]）{
Personp=newPerson（）;
Teachert=newTeacher（）;
inti;
//pointx
}
}
A.i=m;
B.i=b;
C.i=p.a;
D.i=p.change（30）;
E.i=t.b.
6.Whichlayoutmanagerisusedwhentheframeisresizedthebuttons'spositionintheFramemightbechanged
A.BorderLayout
B.FlowLayout
C.CardLayout
D.GridLayout
7.Giventhefollowingcodefragment:
1）publicvoidcreate（）{
2}VectormyVect;
3}myVect=newVector（）;
4}}
Whichofthefollowingstatementsaretrue
A.Thedeclarationonline2doesnotallocatememoryspaceforthevariablemyVect.
B.Thedeclarationonline2allocatesmemoryspaceforareferencetoaVectorobject.
C.Thestatementonline2createsanobjectofclassVector.
D.Thestatementonline3createsanobjectofclassVector.
E.Thestatementonline3allocatesmemoryspaceforanobjectofclassVector
8.Whichofthefollowingansweriscorrecttoexpressthevalue8inoctalnumber
A.
B.0x10
C.08
D.0x8
9.WhicharenotJavakeywords
A.TRUE
B.sizeof
C.const
D.super
E.void
10.Whichofthefollowingstatementsaretrue
A.Theequals（）methoddeterminesifreferencevaluesrefertothesameobject.
B.The==operatordeterminesifthecontentsandtypeoftwoseparateobjectsmatch.
C.Theequals（）methodreturnstrueonlywhenthecontentsoftwoobjectsmatch.
D.TheclassFileoverridesequals（）toreturntrueifthecontentsandtypeoftwoseparateobjectsmatch.
11.Whichstatementsaboutinheritancearetrue
A.InJavaprogramminglanguageonlyallowssingleinheritance.
B.InJavaprogramminglanguageallowsaclasstoimplementonlyone
interface.
C.InJavaprogramminglanguageaclasscannotextendaclassandimplement
ainterfacetogether.
D.InJavaprogramminglanguagesingleinheritancemakescodemore
reliable.
12.
1）classPerson{
2}publicvoidprintValue（inti,intj）{/*…*/}
3}publicvoidprintValue（inti）{/*...*/}
4}}
5）publicclassTeacherextendsPerson{
6}publicvoidprintValue（）{/*...*/}
7}publicvoidprintValue（inti）{/*...*/}
8}publicstaticvoidmain（Stringargs[]）{
9}Persont=newTeacher（）;
10}t.printValue（10）;
11}}
12}}
Whichmethodwillthestatementonline10call
A.online2
B.online3
C.online6
D.online7
13.WhicharenotJavaprimitivetypes
A.short
B.Boolean
C.unit
D.float
14、Themethodresume（）isresponsibleforresumingwhichthread'sexecution
A.Thethreadwhichisstoppedbycallingmethodstop（）
B.Thethreadwhichisstoppedbycallingmethodsleep（）
C.Thethreadwhichisstoppedbycallingmethodwait（）\
D.Thethreadwhichisstoppedbycallingmethodsuspend（）
15.Whichofthefollowingrangeofintiscorrect
A.-2^7–2^7-1
B.0–2^32-1
C.-2^15–2^15-1
D.-2^31–2^31-1
16.Whichkeywordshouldbeusedtoenableinteractionwiththelockofan
objectTheflagallowsexclusiveaccesstothatobject.
A.transient
B.synchronized
C.serialize
D.static
17.Whichisthereturntypeofthemethodmain（）
A.int
B.void
C.boolean
D.static
18.Giventhefollowingcode:
if（x>0）{System.out.println（"first"）;}
elseif（x>-3）{System.out.println（"second"）;}
else{System.out.println（"third"）;}
Whichrangeofxvaluewouldprintthestring"second"
A.x>0
B.x>-3
C.x<=-3
D.x<=0&x>-3
19、Whichofthefollowingansweriscorrecttoexpressthevalue10inhexadecimalnumber
A.0xA
B.0x16
C.0A
D.016
20.Whichstatementsaboutthegarbagecollectionaretrue
A.Theprogramdevelopermustcreateathreadtoberesponsibleforfree
thememory.
B.Thegarbagecollectionwillcheckforandfreememorynolongerneeded.
C.Thegarbagecollectionallowtheprogramdevelopertoexplicityand
immediatelyfreethememory.
D.Thegarbagecollectioncanfreethememoryusedjavaobjectatexpect
time.
21、Giventhefollowingcode:
1）publicclassTest{
2}intm,n;
3}publicTest（）{}
4}publicTest（inta）{m=a;}
5}publicstaticvoidmain（Stringarg[]）{
6}Testt1,t2;
7}intj,k;
8}j=0;k=0;
9}t1=newTest（）;
10}t2=newTest（j,k）;
11}}
12}}
Whichlinewouldcauseoneerrorduringcompilation
A.line3
B.line5
C.line6
D.line10
22、Giventheuncompletedcodeofaclass:
classPerson{
Stringname,department;
intage;
publicPerson（Stringn）{name=n;}
publicPerson（Stringn,inta）{name=n;age=a;}
publicPerson（Stringn,Stringd,inta）{
//doingthesameastwoargumentsversionofconstructor
//includingassignmentname=n,age=a
department=d;
}
}
Whichexpressioncanbeaddedatthe"doingthesameas..."partoftheconstructor
A.Person（n,a）;
B.this（Person（n,a））;
C.this（n,a）;
D.this（name,age）.
23、Whichofthefollowingstatementsaboutvariablesandtheirscopesaretrue
A.Instancevariablesaremembervariablesofaclass.
B.Instancevariablesaredeclaredwiththestatickeyword.
C.Localvariablesdefinedinsideamethodarecreatedwhenthemethodisexecuted.
D.Localvariablesmustbeinitializedbeforetheyareused.
24、publicvoidtest（）{
try{oneMethod（）;
System.out.println（"condition1"）;
}catch（ArrayIndexOutOfBoundsExceptione）{
System.out.println（"condition2"）;
}catch（Exceptione）{
System.out.println（"condition3"）;
}finally{
System.out.println（"finally"）;
}
}
WhichwilldisplayifoneMethodrunnormally
A.condition1
B.condition2
C.condition3
D.finally
25、Giventhefollowingcode:
publicclassTest{
voidprintValue（intm）{
do{System.out.println（"Thevalueis"+m）;
}
while（--m>10）
}
publicstaticvoidmain（Stringarg[]）{
inti=10;
Testt=newTest（）;
t.printValue（i）;
}
}
Whichwillbeoutput
A.Thevalueis8
B.Thevalueis9
C.Thevalueis10
D.Thevalueis11
26、Whichofthefollowingstatementsaboutdeclarationaretrue
A.Declarationofprimitivetypessuchasboolean,byteandsoondoesnotallocatememoryspaceforthevariable.
B.Declarationofprimitivetypessuchasboolean,byteandsoonallocatesmemoryspaceforthevariable.
C.DeclarationofnonprimitivetypessuchasString,Vectorandsoondoesnotallocatememoryspacefortheobject.
D.DeclarationofnonprimitivetypessuchasString,Vectoranssoonallocatesmemoryspacefortheobject.
27、IntheJavaAPIdocumentationwhichsectionsareincludedinaclassdocument
A.Thedescriptionoftheclassanditspurpose
B.Alistofmethodsinitssuperclass
C.Alistofmembervariable
D.Theclasshierarchy
28、Giventhefollowingcode:
1）publicvoidmodify（）{
2）inti,j,k;
3）i=100;
4）while（i>0）{
5）j=i*2;
6）System.out.println（"Thevalueofjis"+j）;
7）k=k+1;
8）i--;
9）}
10}}
Whichlinemightcauseanerrorduringcompilation
A.line4
B.line6
C.line7
D.line8
29、Whichofthefollowingstatementsaboutvariablesandscopearetrue
A.Localvariablesdefinedinsideamethodaredestroyedwhenthemethodisexited.
B.Localvariablesarealsocalledautomaticvariables.
C.Variablesdefinedoutsideamethodarecreatedwhentheobjectisconstructed.
D.Amethodparametervariablecontinuestoexistforaslongastheobjectisneededinwhichthemethodisdefined.
30、Aclassdesignrequiresthatamembervariablecannotbeaccessibledirectlyoutsidetheclass.Whichmodifiershouldbeusedtoobtaintheaccesscontrol
A.public
B.nomodifier
C.protected
D.private
31、Giventhefollowingcodefragment:
1）Stringstr=null;
2）if（（str!
=null）&&（str.length（）>10））{
3}System.out.println（"morethan10"）;
4}}
5）elseif（（str!
=null）&（str.length（）<5））{
6}System.out.println（"lessthan5"）;
7}}
8）else{System.out.println（"end"）;}
Whichlinewillcauseerror
A.line1
B.line2
C.line5
D.line8
32、WhichstatementsaboutJavacodesecurityaretrue
A.Thebytecodeverifierloadsallclassesneededfortheexecutionofaprogram.
B.Executingcodeisperformedbytheruntimeinterpreter.
C.Atruntimethebytecodesareloaded,checkedandruninaninterpreter.
D.Theclassloaderaddssecuritybyseparatingthenamespacesfortheclassesofthelocalfilesystemfromthoseimportedfromnetworksources.
33、Giventhefollowingcode:
publicclassPerson{
intarr[]=newint[10];
publicstaticvoidmain（Stringa[]）{
System.out.println（arr[1]）;
}
}
Whichstatementiscorrect
A.Whencompilationsomeerrorwilloccur.
B.Itiscorrectwhencompilationbutwillcauseerrorwhenrunning.
C.Theoutputiszero.
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