分布式架构第十八单元试题及答案.docx
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分布式架构第十八单元试题及答案
分布式架构第十八单元试题及答案
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下面代码Java变量定义正确的是35.String#name="JaneDoe"36.int%age=24;37.Double_height=123.5;38.double~temp=37.5;[单选题]
第35行
第36行
第37行(正确答案)
第38行
publicclassTestString{publicstaticvoidmain(String[]args){Stringstr="420";str+=42;System.out.println(str);}}输出结果是:
[单选题]
42
420
462
42042(正确答案)
publicclassTest{publicstaticvoidmain(String[]args){intx=5;booleanb1=true;booleanb2=false;if((x==4)&&!
b2)System.out.println("1");System.out.println("2");if((b2=true)&&b1)System.out.println("3");}}输出结果是:
[单选题]
2
3
12
23(正确答案)
publicvoidgo(){Stringo="";z:
for(intx=0;i<3;x++){for(inty=0;y<2;y++){if(x==1)break;if(x==2&&y==1)breakz;o=o+x+y;}}System.out.println(o);}输出结果是:
[单选题]
00
0001
000120(正确答案)
00012021
intx=0;inty=10;do{y--;++x;}while(x<5);System.out.println(x+","+y);输出结果是:
[单选题]
5,6
5,5(正确答案)
6,5
6,6
publicclassBreaker{staticStringo="";publicstaticvoidmain(String[]args){z:
o=o+2;for(intx=3;x<8;x++){if(x==4)break;if(x==6)breakz;o=o+x;}System.out.println(o);}}输出结果是:
[单选题]
23
234
234567
编译错误(正确答案)
publicclassBreaker2{staticStringo="";publicstaticvoidmain(String[]args){z:
for(intx=2;x<7;x++){if(x==3)continue;if(x==5)breakz;o=o+x;}System.out.println(o);}}输出结果是:
[单选题]
2
24(正确答案)
234
编译错误
publicclassSpock{publicstaticvoidmain(String[]args){Longtail=2000L;Longdistance=1999L;Longstory=1000L;if((tail>distance)^((story*2)==tail))System.out.println("1");if((distance+1!
=tail)^((story*2)==distance))System.out.println("2");}}输出结果是:
[单选题]
1
2
12
无输出(正确答案)
String[]elements={"for","tea","too"};Stringfirst=(elements.length>0)?
elements[0]:
null;输出结果是:
[单选题]
编译错误
运行时抛出异常
first赋值为null
first赋值为elements[0](正确答案)
importjava.util.*;publicclassQuest{publicstaticvoidmain(String[]args){String[]colors={"blue","red","green","yellow","orange"};Arrays.sort(colors);ints2=Arrays.binarySearch(colors,"orange");ints3=Arrays.binarySearch(colors,"violet");System.out.println(s2+""+s3);}}输出结果是:
[单选题]
2-1
2-4
2-5(正确答案)
编译错误
classAlligator{publicstaticvoidmain(String[]args){int[]x[]={{1,2},{3,4,5},{6,7,8,9}};int[][]y=x;System.out.println(y[2][1]);}}输出结果是:
[单选题]
2
3
7(正确答案)
编译错误
publicclassBarn{publicstaticvoidmain(String[]args){newBarn().go("hi",1);newBarn().go("hi","world",2);}publicvoidgo(String...y,intx){System.out.println(y[y.length-1]+"");}}输出结果是:
[单选题]
hihi
hiworld
worldworld
编译错误(正确答案)
classPerson{Stringname="Noname";publicPerson(Stringnm){name=nm;}}classEmployeeextendsPerson{StringempId="0000";publicEmployee(Stringid){empId=id;}}classEmployeeTest{publicstaticvoidmain(String[]args){Employeee=newEmployee("4321");System.out.println(e.empId);}}输出结果是:
[单选题]
4321
0000
运行时抛出异常
编译错误(正确答案)
classMud{//将下面代码放到这里,System.out.println("hi");}}一共有多少选项可以正常编译publicstaticvoidmain(String...a){publicstaticvoidmain(String.*a){publicstaticvoidmain(String...a){publicstaticvoidmain(String[]...a){publicstaticvoidmain(String...[]a){[单选题]
0
1
2
3(正确答案)
classAtom{Atom(){System.out.print("atom");}}classRockextendsAtom{Rock(Stringtype){System.out.print(type);}}publicclassMountainextendsRock{Mountain(){super("granite");newRock("granite");}publicstaticvoidmain(String[]a){newMountain();}}输出结果是:
[单选题]
编译错误
atomgranite
granitegranite(正确答案)
atomgraniteatomgranite
publicclassBlip{protectedintblipvert(intx){return0;}}classVertextendsBlip{//下面代码放在这里}1.publicintblipvert(intx){return0;}2.privateintblipvert(intx){return0;}3.privateintblipvert(longx){return0;}4.protectedlongblipvert(intx){return0;}5.protectedintblipvert(longx){return0;}6.protectedlongblipvert(longx){return0;}7.protectedlongblipvert(intx,inty){return0;}一共有多少选项放在上面可以正常编译[单选题]
0
2
4
5(正确答案)
1.classSuper2.{3.privateinta;4.protectedSuper(inta){this.a=a;}5.}6.classSubextendsSuper7.{8.publicSub(inta){super(a);}9.publicSub(){this.a=5;}10.}上面代码如下修改可以编译通过[单选题]
修改第2行为publicinta;
修改第2行为protectedinta;
修改第13行为publicSub(){this(5);}(正确答案)
修改第13行为publicSub(){super(a);}
classBatman{intsquares=81;publicstaticvoidmain(String[]args){newBatman().go();}voidgo(){incr(++squares);System.out.println(squares);}voidincr(intsquares){squares+=10;}}输出结果是:
[单选题]
81
82(正确答案)
91
92
classPass{publicstaticvoidmain(String[]args){intx=5;Passp=newPass();p.doStuff(x);System.out.println("mainx="+x);}voiddoStuff(intx){System.out.println("doStuffx="+x++);}}输出结果是:
[单选题]
编译错误
运行时抛出异常
doStuffx=6mainx=6
doStuffx=5mainx=5(正确答案)
classClassA{publicintnumberOfInstances;protectedClassA(intnumberOfInstances){this.numberOfInstances=numberOfInstances;}}classExtendedAextendsClassA{privateExtendedA(intnumberOfInstances){super(numberOfInstances);}publicstaticvoidmain(String[]args){ExtendedAext=newExtendedA(420);System.out.println(ext.numberOfInstances);}}输出结果是:
[单选题]
420(正确答案)
运行时抛出异常
所有构造方法必须声明为public
构造方法不能声明为私有
classOne{voidfoo(){}}classTwoextendsOne{//下面代码放在这里}一共有多少选项可以放在上面可以正常编译1.intfoo(){}2.voidfoo(){}3.publicvoidfoo(){}4.privatevoidfoo(){}5.protectedvoidfoo(){}[单选题]
0
1
3(正确答案)
2
classX{X(){System.out.print
(1);}X(intx){this();System.out.print
(2);}}publicclassYextendsX{Y(){super(6);System.out.print(3);}Y(inty){this();System.out.println(4);}publicstaticvoidmain(String[]a){newY(5);}}输出结果是:
[单选题]
13
134
1234(正确答案)
2134
publicclassHi{voidm1(){}protectedvoidm2(){}}classLoisextendsHi{// 下面哪些代码可以放在这里}输出结果是:
publicvoidm1(){}(正确答案)
protectedvoidm1(){}(正确答案)
privatevoidm1(){}
voidm2(){}
classOne{publicOnefoo(){returnthis;}}classTwoextendsOne{publicOnefoo(){returnthis;}}classThreeextendsTwo{//下面哪些代码可以放在这里}A.publicvoidfoo(){}B.publicintfoo(){return3;}C.publicTwofoo(){returnthis;}D.publicOnefoo(){returnthis;}
publicvoidfoo(){}
publicintfoo(){return3;}
publicTwofoo(){returnthis;}(正确答案)
publicOnefoo(){returnthis;}(正确答案)
classEmployee{Stringname;doublebaseSalary;publicEmployee(Stringname,doublebaseSalary){this.name=name;this.baseSalary=baseSalary;}}publicclassSalesPersonextendsEmployee{doublecommission;publicSalesPerson(Stringname,doublebaseSalary,doublecommission){//下面哪些代码可以放在这里编译运行}}
super(name,baseSalary);(正确答案)
mission=commission;
super();mission=commission;
super(name,baseSalary);mission=commission;(正确答案)
publicabstractclassShape{privateintx;privateinty;publicabstractvoiddraw();publicvoidsetAnchor(intx,inty){this.x=x;this.y=y;}}下面定义正确的是:
publicclassCircleimplementsShape{privateintradius;}
publicabstractclassCircleextendsShape{privateintradius;}(正确答案)
publicclassCircleextendsShape{privateintradius;publicvoiddraw();}
publicclassCircleextendsShape{privateintradius;publicvoiddraw(){};}(正确答案)
classClassA{}classClassBextendsClassA{}classClassCextendsClassA{}ClassAp0=newClassA();ClassBp1=newClassB();ClassCp2=newClassC();ClassAp3=newClassB();ClassAp4=newClassC();下面哪几个赋值语句是合法的
p0=p1(正确答案)
p1=p2
p1=(ClassB)p3(正确答案)
p2=(ClassC)p4(正确答案)
classThingy{Meterm=newMeter();}classComponent{voidgo(){System.out.print("c");}}classmeterextendsComponent{voidgo(){System.out.print("m");}}classDeluxeThingyextendsThingy{publicstaticvoidmain(String[]args){DeluxeThingydt=newDeluxeThingy();dt.m.go();Thingyt=newDeluxeThingy();t.m.go();}}下面描述正确的是:
输出mm(正确答案)
输出mc
DeluxeThingyhas-aComponent(正确答案)
以上都不对
abstractpublicclassEmployee{protectedabstractdoublegetSaleAmount();publicdoublegetCommision(){returngetSalesAmount()*0.15;}}classSalesextendsEmployee{//下面哪些代码放在这里可以正确运行}
doublegetSalesAmount(){return1230.45;}
publicdoublegetSalesAmount(){return1230.45;}(正确答案)
privatedoublegetSalesAmount(){return1230.45;}
protecteddoublegetSalesAmount(){return1230.45;}(正确答案)
publicinterfaceStatus{/*下面哪些修饰符可以放在这里*/intMY_VALUE=10;}
final(正确答案)
static(正确答案)
native
public(正确答案)
下面哪些类正确实现java.lang.Runnable和java.lang.Cloneable接口
publicclassSessionimplementsRunnable,Cloneable{publicvoidrun();publicObjectclone();}
publicclassSessionextendsRunnable,Cloneable{publicvoidrun(){...}publicObjectclone(){...}}
publicclassSessionimplementsRunnable,Cloneable{publicvoidrun(){...}publicObjectclone(){...}}(正确答案)
publicabstractclassSessionimplementsRunnable,Cloneable{publicvoidrun(){...}publicObjectclone(){...}}(正确答案)
10.interfaceFoo{11.intbar();12.}13.14.publicclassBeta{15.16.classAimplementsFoo{17.publicintbar(){return1;}18.}19.20.publicintfubar(Foofoo){returnfoo.bar();}21.22.publicvoidtestFoo(){23.24.ClassAimplementsFoo{25.publicintbar(){return2;}26.}27.28.System.out.println(fubar(newA()));29.}30.31.publicstaticvoidmain(String[]argv){32.newBeta().testFoo();33.}34.}下面哪些语句是正确的
编译错误
代码可以编译,运行输出2(正确答案)
如果第16,17,18行删除,输出2(正确答案)
如果第24,25,26行删除,输出1(正确答案)
Java语言是编译类型语言[判断题]
对
错(正确答案)
同一个JVM中同一个的类可以被加载多次[判断题]
对(正确答案)
错
long类型8个字节,float类型4个字节,long类型中最大数比float类型中最大的数要更大[判断题]
对
错(正确答案)
Java语言无法调用C语言编写的DLL动态链接库[判断题]
对
错(正确答案)
在Java语言中字符'A'占一个字节,汉字'中'占两个字节[判断题]
对
错(正确答案)
在Java语言中int和char类型可以相互转换[判断题]
对(正确答案)
错
在Java语言中可以集成父类的方法和属性,我们可以写一个类继承java.lang.String[判断题]
对
错(正确答案)
Java语言中,有八种基本数据类型[判断题]
对(正确答案)
错
Java可以开发桌面程序,也可以开发服务器端程序[判断题]
对(正确答案)
错
Java类中启动方法可以是publicstaticvoidmain(String…arg)[判断题]
对(正确答案)
错