JAVA认证 147道SCJP考试试题精解.docx
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JAVA认证147道SCJP考试试题精解
JAVA认证：
147道SCJP考试试题精解
LeadingthewayinITtestingandcertificationtools,
QuestionNo:
1
Given:
1.publicclasstest（
2.publicstaticvoidmain（Stringargs[]）{
3.inti=0xFFFFFFF1;
4.intj=~i;
5.
6.}
7.）
Whatisthedecimalvalueofjatline5?
A.0
B.1
C.14
D.–15
E.Anerroratline3causescompilationtofail.
F.Anerroratline4causescompilationtofail.
Answer:
C
QuestionNo:
2
Given:
Integeri=newInteger（42）;
Long1=newLong（42）;
Doubled=newDouble（42.0）;
WhichtwoexpressionsevaluatetoTrue?
（ChooseTwo）
A.（i==1）
B.（i==d）
C.（d==1）
D.（i.equals（d））
E.（d.equals（i））
F.（i.equals（42））
Answer:
D,E
QuestionNo:
3
Exhibit:
1.publicclasstest（
2.privatestaticintj=0;
3.
4.privatestaticbooleanmethodB（intk）（
5.j+=k;
6.returntrue;
6.）
7.
8.publicstaticvoidmethodA（inti）{
9.booleanb:
10.b=i<10|methodB（4）;
11.b=i<10||methodB（8）;
12.）
13.
14.publicstaticvoidmain（Stringargs[]}（
15.methodA（0）;
16.system.out.printIn（j）;
17.）
18.）
Whatistheresult?
A.Theprogramprints“0”
B.Theprogramprints“4”
C.Theprogramprints“8”
D.Theprogramprints“12”
E.Thecodedoesnotcomplete.
Answer:
B
QuestionNo:
4
Given
1.Publicclasstest（
2.Publicstaticvoidmain（Stringargs[]）（
3.System.out.printIn（6^3）;
4.）
5.）
Whatistheoutput?
Answer:
5
QuestionNo:
5
Given:
1.publicclassFoo{
2.publicstaticvoidmain（String[]args）{
3.StringBuffera=newStringBuffer（“A”）;
4.StringBufferb=newStringBuffer（“B”）;
5.operate（a,b）;
6.system.out.printIn{a+“,”+b};
7.）
8.staticvoidoperate（StringBufferx,StringBuffery）{
9.x.append{y};
10.y=x;
11.）
12.}
Whatistheresult?
A.Thecodecompilesandprints“A,B”.
B.Thecodecompilesandprints“A,A”.
C.Thecodecompilesandprints“B,B”.
D.Thecodecompilesandprints“AB,B”.
E.Thecodecompilesandprints“AB,AB”.
F.Thecodedoesnotcompilebecause“+”cannotbeoverloadedforStringBuffer.
Answer:
D
QuestionNo:
6
Exhibit:
1.Publicclasstest（
2.PublicstaticvoidstringReplace（Stringtext）（
3.Text=text.replace（‘j',‘i'）;
4.）
5.
6.publicstaticvoidbufferReplace（StringBuffertext）（
7.text=text.append（“C”）
8.）
9.
10.publicstaticvoidmain（Stringargs[]}（
11.StringtextString=newString（“java”）;
12.StringBuffertextBufferString=newStringBuffer（“java”）;
13.
14.stringReplace（textString）;
15.BufferReplace（textBuffer）;
16.
17.System.out.printIn（textString+textBuffer）;
18.}
19.）
Whatistheoutput?
Answer:
javajavaC
QuestionNo:
7
Exhibit:
1.publicclasstest{
2.publicstaticvoidadd3（Integeri）}
3.intval=i.intValue（）;
4.val+=3;
5.i=newInteger（val）;
6.}
7.
8.publicstaticvoidmain（Stringargs[]）{
9.Integeri=newInteger（0）;
10.add3（i）;
11.system.out.printIn（i.intValue（））;
12.}
13.）
Whatistheresult?
A.Compilationwillfail.
B.Theprogramprints“0”.
C.Theprogramprints“3”.
D.Compilationwillsucceedbutanexceptionwillbethrownatline3.
Answer:
B
QuestionNo:
8
Given:
1.publicclassConstOver{
2.publicConstOver（intx,inty,intz）{
3.}
4.}
WhichtwooverloadtheConstOverconstructor?
（ChooseTwo）
A.ConstOver（）{}
B.ProtectedintConstOver（）{}
C.PrivateConstOver（intz,inty,bytex）{}
D.PublicObjectConstOver（intx,inty,intz）{}
E.PublicvoidConstOver（bytex,bytey,bytez）{}
Answer:
A,C
QuestionNo:
9
Given:
1.publicclassMethodOver{
2.publicvoidsetVar（inta,intb,floatc）{
3.}
4.}
WhichtwooverloadthesetVarmethod?
（ChooseTwo）
A.PrivatevoidsetVar（inta,floatc,intb）{}
B.ProtectedvoidsetVar（inta,intb,floatc）{}
C.PublicintsetVar（inta,floatc,intb）（returna;）
D.PublicintsetVar（inta,intb,floatc）（returna;）
E.ProtectedfloatsetVar（inta,intb,floatc）（returnc;）
Answer:
A,C
QuestionNo:
10
Given:
1.classBaseClass{
2.Privatefloatx=1.0f;
3.protectedfloatgetVar（）（returnx;）
4.}
5.classSubclassextendsBaseClass（
6.privatefloatx=2.0f;
7.//insertcodehere
8.）
Whichtwoarevalidexamplesofmethodoverriding?
（ChooseTwo）
A.FloatgetVar（）{returnx;}
B.PublicfloatgetVar（）{returnx;}
C.FloatdoublegetVar（）{returnx;}
D.PublicfloatgetVar（）{returnx;}
E.PublicfloatgetVar（floatf）{returnf;}
Answer:
B,D
QuestionNo:
11
Whichtwodemonstratean“isa”relationship?
（ChooseTwo）
A.publicinterfacePerson{}
publicclassEmployeeextendsPerson{}
B.publicinterfaceShape{}
publicclassEmployeeextendsShape{}
C.publicinterfaceColor{}
publicclassEmployeeextendsColor{}
D.publicclassSpecies{}
publicclassAnimal（privateSpeciesspecies;）
E.interfaceComponent{}
ClassContainerimplementsComponent（
PrivateComponent[]children;
）
Answer:
D,E
QuestionNo:
12
Whichstatementistrue?
A.Ananonymousinnerclassmaybedeclaredasfinal.
B.Ananonymousinnerclasscanbedeclaredasprivate.
C.Ananonymousinnerclasscanimplementmultipleinterfaces.
D.Ananonymousinnerclasscanaccessfinalvariablesinanyenclosingscope.
E.Constructionofaninstanceofastaticinnerclassrequiresaninstanceoftheenclosingouterclass.
Answer:
D
QuestionNo13
Given:
1.packagefoo;
2.
3.publicclassOuter（
4.publicstaticclassInner（
5.）
6.）
Whichstatementistrue?
A.AninstanceoftheInnerclasscanbeconstructedwith“newOuter.Inner（）”
B.Aninstanceoftheinnerclasscannotbeconstructedoutsideofpackagefoo.
C.Aninstanceoftheinnerclasscanonlybeconstructedfromwithintheouterclass.
D.Fromwithinthepackagebar,aninstanceoftheinnerclasscanbeconstructedwith“newinner（）”
Answer:
A
QuestionNo14
Exhibit:
1.publicclassenclosingone（
2.publicclassinsideone{}
3.）
4.publicclassinertest（
5.publicstaticvoidmain（string[]args）（
6.enclosingoneeo=newenclosingone（）;
7.//insertcodehere
8.）
9.）
Whichstatementatline7constructsaninstanceoftheinnerclass?
A.InsideOnewei=eo.newInsideOn（）;
B.Eo.InsideOneei=eo.newInsideOne（）;
C.InsideOneei=EnclosingOne.newInsideOne（）;
D.EnclosingOne.InsideOneei=eo.newInsideOne（）;
Answer:
D
QuestionNo15
Exhibit:
1.interfacefoo{
2.intk=0;
3.]
4.
5.publicclasstestimplementsFoo（
6.publicstaticvoidmain（Stringargs[]）（
7.inti;
8.Testtest=newtest（）;
9.i=test.k;
10.i=Test.k;
11.i=Foo.k;
12.）
13.）
14.
Whatistheresult?
A.Compilationsucceeds.
B.Anerroratline2causescompilationtofail.
C.Anerroratline9causescompilationtofail.
D.Anerroratline10causescompilationtofail.
E.Anerroratline11causescompilationtofail.
Answer:
A
QuestionNo16
Given:
1.//pointX
2.publicclassfoo（
3.publicstaticvoidmain（String[]args）throwsException{
4.printWriterout=newPrintWriter（new
5.java.io.outputStreamWriter（System.out）,true;
6.out.printIn（“Hello”）;
7.}
8.）
WhichstatementatPointXonline1allowsthiscodetocompileandrun?
A.Importjava.io.PrintWriter;
B.Includejava.io.PrintWriter;
C.Importjava.io.OutputStreamWriter;
D.Includejava.io.OutputStreamWriter;
E.Nostatementisneeded.
Answer:
A
QuestionNo17
WhichtwostatementsarereservedwordsinJava?
（ChooseTwo）
A.Run
B.Import
C.Default
D.Implement
Answer:
B,C
QuestionNo18
Whichthreearevaliddeclarationsofafloat?
（ChooseThree）
A.Floatfoo=-1;
B.Floatfoo=1.0;
C.Floatfoo=42e1;
D.Floatfoo=2.02f;
E.Floatfoo=3.03d;
F.Floatfoo=0x0123;
Answer:
A,D,F
LeadingthewayinITtestingandcertificationtools,
QuestionNo19
Given:
8.intindex=1;
9.boolean[]test=newBoolean[3];
10.booleanfoo=test[index];
Whatistheresult?
A.Foohasthevalueof0.
B.Foohasthevalueofnull.
C.Foohasthevalueoftrue.
D.Foohasthevalueoffalse.
E.Anexceptionisthrown.
F.Thecodewillnotcompile.
Answer:
D
QuestionNo20
Given:
1.publicclasstest（
2.publicstaticvoidmain（string[]args）{
3.stringfoo=args[1];
4.stringfoo=args[2];
5.stringfoo=args[3];
6.}
7.}
Andcommandlineinvocation:
JavaTestredgreenblue
Whatistheresult?
A.Bazhasthevalueof“”
B.Bazhasthevalueofnull
C.Bazhasthevalueof“red”
D.Bazhasthevalueof“blue”
E.Baxhasthevalueof“green”
F.Thecodedoesnotcompile.
G.Theprogramthrowsanexception.
Answer:
G
QuestionNo21
Given:
8.intindex=1;
9.int[]foo=newint[3];
10.intbar=foo[index];
11.intbaz=bar+index;
Whatistheresult?
A.Bazhasthevalueof0
B.Bazhasthevalueof1
C.Bazhasthevalueof2
D.Anexceptionisthrown.
E.Thecodewillnotcompile.
Answer:
B
QuestionNo22
Given:
1.publicclassfoo{
2.publicstaticvoidmain（String[]args）{
3.Strings;
4.system.out.printIn（“s=”+s）;
5.}
6.}
Whatistheresult?
A.Thecodecompilesand“s=”isprinted.
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