SCJP题库Word文档格式.docx
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21.System.out.print("
3"
22.}
23.}
Whatistheresult?
A.2
B.3
C.12
D.23
E.123
F.Compilationfails.
G.Anexceptionalisthrownatruntime.
D注意20行,=为赋值,不要被骗
Question3
42.publicclassClassA{
43.publicintgetValue(){
44.intvalue=0;
45.booleansetting=true;
46.Stringtitle="
Hello"
47.if(value||(setting&
title=="
)){return1;
}
48.if(value==1&
title.equals("
)){return2;
49.}
50.}
And:
70.ClassAa=newClassA();
71.a.getValue();
A.1
B.2
C.Compilationfails.
D.Thecoderunswithnooutput.
E.Anexceptionisthrownatruntime.
C编译不通过,47行value为int类型不是boolean
Question4
11.publicvoidtestIfA(){
12.if(testIfB("
True"
)){
13.System.out.println("
14.}else{
15.System.out.println("
Nottrue"
16.}
17.}
18.publicBooleantestIfB(Stringstr){
19.returnBoolean.valueOf(str);
20.}
WhatistheresultwhenmethodtestIfAisinvoked?
A.True
B.Nottrue
C.Anexceptionisthrownatruntime.
D.Compilationfailsbecauseofanerroratline12.
E.Compilationfailsbecauseofanerroratline19.
A19行,如果str为true则返回ture,否则返回false
Question5
11.publicstaticvoidmain(String[]args){
12.Integeri=newInteger
(1)+newInteger
(2);
13.switch(i){
14.case3:
System.out.println("
three"
break;
15.default:
other"
A.three
B.other
D.Compilationfailsbecauseofanerroronline12.
E.Compilationfailsbecauseofanerroronline13.
F.Compilationfailsbecauseofanerroronline15.
A就是两个Integer类型相加
Question6
12.Stringstr="
null"
13.if(str==null){
14.System.out.println("
15.}else(str.length()==0){
16.System.out.println("
zero"
17.}else{
18.System.out.println("
some"
19.}
‘Whatistheresult?
A.null
B.zero
C.some
D.Compilationfails.
D这题真恶心15行少个if
Question7
10.intx=0;
11.inty=10;
12.do{
l3.y--;
14.++x;
15.}while(x<
5);
16.System.out.print(x+"
"
+y);
A.5,6
B.5,5
C.6,5
D.6,6
B(91,82,73,64,55)没啥争议
Question8
25.intx=12;
26.while(x<
10){
27.x--;
28.}
29.System.out.print(x);
A.0
B.10
C.12
D.Line29willneverbereached.
C12>
10,所以直接跳出循环,输出x=12
Question9
35.intx=10;
36.do{
37.x--;
38.}while(x<
10);
Howmanytimeswillline37beexecuted?
A.tentimes
B.zerotimes
C.onetometimes
D.morethantentimes
D死循环
Question10
12.for(inti=0;
i<
=10;
i++){
13.if(i>
6)break;
14.}
15.System.out.println(i);
A.6
B.7
C.10
D.11
E.Compilationfails.
F.Anexceptionisthrownatruntime.
E15行i超出了作用域
Question11
55.int[]x={1,2,3,4,5};
56.inty[]=x;
57.System.out.println(y[2]);
Whichistrue?
A.Line57willprintthevalue2.
B.Line57willprintthevalue3.
C.Compilationwillfailbecauseofanerrorinline55.
D.Compilationwillfailbecauseofanerrorinline56.
B没争议,考察数组下标是从0开始
Question12
Whichtwocodefragments(片段)correctly(正确)createandinitializeastaticarrayofintelements?
A.staticfinalint[]a={100,200};
B.staticfinalint[]a;
static{a=newint[2];
a[0]=100;
a[1]=200;
C.staticfinalint[]a=newint[2]{100,200};
D.staticfinalint[]a;
staticvoidinit(){a=newint[3];
ABc不能指定长度,d不能在init方法中赋值,要么在static代码块中
Question13
12.Objectobj=newint[]{1,2,3};
13.int[]someArray=(int[])obj;
14.for(inti:
someArray)System.out.print(i+"
"
)
15.}
A.123
B.Compilationfailsbecauseofanerrorinline12.
C.Compilationfailsbecauseofanerrorinline13.
D.Compilationfailsbecauseofanerrorinline14.
E.AClassCastExceptionisthrownatruntime.
A没争议,foeach循环遍历数组
Question14
11.String[]elements={"
for"
"
tea"
too"
};
12.Stringfirst=(elements.length>
0)?
elements[0]:
null;
A.Compilationfails.
B.Anexceptionisthrownatruntime.
C.Thevariablefirstissettonull.
D.Thevariablefirstissettoelements[0].
D
Question15
10.publicclassBar{
11.staticvoidfoo(int...x){
12.//insertcodehere
13.}
Whichtwocodefragments,insertedindependently(独立的)atline12,willallowtheclasstocompile?
A.foreach(x)System.out.println(z);
B.for(intz:
x)System.out.println(z);
C.while(x.hasNext())System.out.println(x.next());
D.for(inti=0;
i<
x.length;
i++)System.out.println(x[i]);
BDx相当于一个数组,a明显错没有foreach,c中x没有hadNext方法
Question16
Aprogrammer(程序员)needstocreatealoggingmethodthatcanaccept(接受)anarbitrary(随意任意)numberofarguments.Forexample,itmaybecalledinthese
ways:
logIt("
logmessage1"
logmessage2”,”logmessage3"
logmessage4"
logmessage5"
logmessage6"
Whichdeclaration(说明)satisfies(符合)thisrequirement(需求)?
A.publicvoidlogIt(String*msgs)
B.publicvoidlogIt(String[]msgs)
C.publicvoidlogIt(String...msgs)
D.publicvoidlogIt(Stringmsg1,Stringmsg2,Stringmsg3)
C可变长参数
Question17
1.publicclassA{
2.publicStringdoit(intx,inty){
3.return"
a"
4.}
5.
6.publicStringdoit(int...vals){
7.return"
b"
8.}
9.}
25.Aa=newA();
26.System.out.println(a.doit(4,5));
A.Line26prints"
toSystem.out.
B.Line26prints"
C.Anexceptionisthrownatline26atruntime.
D.CompilationofclassAwillfailduetoanerrorinline6.
A确定参数和可变长参数同时存在的时候,优先考虑确定参数的
Question18
GivenafileGrizzlyBear.java:
1.packageanimals.mammals;
2.
3.publicclassGrizzlyBearextendsBear{
4.voidhunt(){
5.Salmons=findSalmon();
6.s.consume();
7.}
andanotherfile,Salmon.java:
1.packageanimals.fish;
3.publicclassSalmonextendsFish{
4.voidconsume(){/*dostuff*/}
5.}
Assume(假定)bothclassesaredefinedinthecorrectdirectoriesfortheftpackages,andthattheMammalclasscorrectlydefinesthefindSalmon()method.Whichtwochangesallowthiscodetocompilecorrectly?
A.addpublictothestartofline4inSalmon.java
B.addpublictothestartofline4inGrizzlyBear.java
C.addimportanimals.mammals.*;
atline2inSalmon.java
D.addimportanimals.fish.*;
atline2inGrizzlyBear.java
E.addimportanimals.fish.Salmon.*;
F.addimportanimals.mammals.GrizzlyBear.*;
atline2inSalmon.java
AD调用不同包下的类,要先导入,方法权限要设置成public
Question19
10.packagecom.sun.scjp;
11.publicclassGeodetics{
12.publicstaticfinaldoubleDIAMETER=12756.32;
//kilometers
Whichtwocorrectlyaccess(访问)theDIAMETERmemberoftheGeodeticsclass?
A.importcom.sun.scjp.Geodetics;
publicclassTerraCarta{
publicdoublehalfway()
{returnGeodetics.DIAMETER/2.0;
}}
B.importstaticcom.sun.scjp.Geodetics;
publicdoublehalfway(){returnDIAMETER/2.0;
C.importstaticcom.sun.scjp.Geodetics.*;
D.packagecom.sun.scjp;
ACb中不能静态导入类,c中静态导入类属性,正确,d访问错误很明显
Question20
Givenclassesdefinedintwodifferentfiles:
1.packageutil;
2.publicclassBitUtils{
3.privatestaticvoidprocess(byte[]b){}
1.packageapp;
2.publicclassSomeApp{
3.publicstaticvoidmain(String[]args){
4.byte[]bytes=newbyte[256];
5.//insertcodehere
6.}
Whatisrequired(必需的)atline5inclassSomeApptousetheprocessmethod
ofBitUtils?
A.process(bytes);
B.BitUtils.process(bytes);
C.app.BitUtils.process(bytes);
D.util.BitUtils.process(bytes);
E.importutil.BitUtils.*;
process(bytes);
F.SomeAppcannotusetheprocessmethodinBitUtils.
F私有的,不能被访问
Question21
GivenaclassRepetition(重复):
1.packageutils;
3.publicclassRepetition{
4.publicstaticStringtwice(Strings){returns+s;
andgivenanotherclassDemo:
1.//insertcodehere
3.publicclassDemo{
4.publicstaticvoidmain(String[]args){
5.System.out.println(twice("
pizza"
));
Whichcodeshouldbeinsertedatline1ofDemo.javatocompileandrunDemotoprint“pizzapizza”?
A.importutils.*;
B.staticimportutils.*;
C.importutils.Repetition.*;
D.staticimportutils.Repetition.*;
E.importutils.Repetition.twice();
F.importstaticutils.Repetition.twice;
G.staticimportutils.Repetition.twice;
F静态导入
Question22
1.packagetest;
3.classTarget(目标){
4.publicStringname="
hello"
Whatcandirectly(直接的)accessandchangethevalueofthevariable(变量)name?
A.anyclas