笔试.docx
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笔试.docx
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笔试
选择题
1:
whichmodifiershouldbeappliedtoamethodforthelockofobjectthistobeobtainedpriortoexcutionanyofthemethodbody?
a.synchronized
b.abstract
c.final
d.static
2:
givethefollowingjavasourcefragement:
//pointx
publicclassinteresting{
//dosomething
}
whichstatementiscorrectlyjavasyntaxatpointx?
givethefollowingjavasourcefragement:
//pointx
publicclassinteresting{
//dosomething
}
whichstatementiscorrectlyjavasyntaxatpointx?
a.publicclassmyclass{//dootherthing…}
b.staticintpi=3.14
c.classmyclass{//dosomething…}
d.none
3:
whatistheresultwhenyoucompileandrunthefollowingcode?
publicclasstest
{
publicvoidmethod()
{
for(inti=0;i<3;i++)
{
system.out.print(i);
}
system.out.print(i);
}
}
choices:
whatistheresultwhenyoucompileandrunthefollowingcode?
publicclasstest
{
publicvoidmethod()
{
for(inti=0;i<3;i++)
{
system.out.print(i);
}
system.out.print(i);
}
}
choices:
a.0122
b.0123
pilationerror
d.noneofthese
4:
whichofthefollowingstatementsaretrue?
a.theautomaticgarbagecollectionofthejvmpreventsprogramsfromeverrunningoutofmemory
b.aprogramcansuggestthatgarbagecollectionbeperformedandforceit
c.garbagecollectionisplatformindependent
d.anobjectbecomeseligibleforgarbagecollectionwhenallreferencesdenotingitaresettonull.
5:
givethefollowingmethod:
publicvoidmethod(){
stringa,b;
a=newstring(“helloworld”);
b=newstring(“gameover”);
system.out.println(a+b+”ok”);
a=null;
a=b;
system.out.println(a);
}
intheabsenceofcompileroptimization,whichistheearliestpointtheobjectareferedisdefinitelyelibiletobegarbagecollection.
givethefollowingmethod:
publicvoidmethod(){
stringa,b;
a=newstring(“helloworld”);
b=newstring(“gameover”);
system.out.println(a+b+”ok”);
a=null;
a=b;
system.out.println(a);
}
intheabsenceofcompileroptimization,whichistheearliestpointtheobjectareferedisdefinitelyelibiletobegarbagecollection.
a.beforeline5
b.beforeline6
c.beforeline7
d.beforeline9
6:
givethisclassoutline:
classexample{
privateintx;
//restofclassbody…
}
assumingthatxinvokedbythecodejavaexample,whichstatementcanmadexbedirectlyaccessibleinmain()methodofexample.java?
givethisclassoutline:
classexample{
privateintx;
//restofclassbody…
}
assumingthatxinvokedbythecodejavaexample,whichstatementcanmadexbedirectlyaccessibleinmain()methodofexample.java?
a.changeprivateintxtopublicintx
b.changeprivateintxtostaticintx
c.changeprivateintxtoprotectedintx
d.changeprivateintxtofinalintx
7:
giventhefollowingclassdefinition:
classa{
protectedinti;
a(inti){
this.i=i;
}
}
whichofthefollowingwouldbeavalidinnerclassforthisclass?
selectvalidanswer:
giventhefollowingclassdefinition:
classa{
protectedinti;
a(inti){
this.i=i;
}
}
whichofthefollowingwouldbeavalidinnerclassforthisclass?
selectvalidanswer:
a.classb{}
b.classbextendsa{}
c.classbextendsa{b(){system.out.println(“i=”+i);}}
d.classb{classa{}}
8:
软件生命周期的瀑布模型把软件项目分为3个阶段、8个子阶段,以下哪一个是正常的开发顺序?
a.计划阶段、开发阶段、运行阶段
b.设计阶段、开发阶段、编码阶段
c.设计阶段、编码阶段、维护阶段
d.计划阶段、编码阶段、测试阶段
9:
whathappenswhenyoutrytocompileandrunthefollowingprogram?
classmystery{
strings;
publicstaticvoidmain(string[]args){
mysterym=newmystery();
m.go();
}
voidmystery(){
s=”constructor”;
}
voidgo(){
system.out.println(s);
}
}
whathappenswhenyoutrytocompileandrunthefollowingprogram?
classmystery{
strings;
publicstaticvoidmain(string[]args){
mysterym=newmystery();
m.go();
}
voidmystery(){
s=”constructor”;
}
voidgo(){
system.out.println(s);
}
}
a.thiscodecomplilesbutthrowsanexceptionatruntime
b.thiscoderunsbutnothingappearsinthestandardoutput
c.thiscoderunsand“constructor”inthestandardoutput
d.thiscoderunsandwrites”null”inthestandardoutput
10:
givethefollowingjavaclass:
publicclassexample{
publicstaticvoidmain(stringargs[]){
staticintx[]=newint[15];
system.out.println(x[5]);
}
}
whichstatementiscorrected?
givethefollowingjavaclass:
publicclassexample{
publicstaticvoidmain(stringargs[]){
staticintx[]=newint[15];
system.out.println(x[5]);
}
}
whichstatementiscorrected?
a.whencompile,someerrorwilloccur.
b.whenrun,someerrorwilloccur.
c.outputiszero.
d.outputisnull.
11:
publicclassx{
publicobjectm(){
objecto=newfloat(3.14f);//line3
object[]oa=newobject[1];//line4
oa[0]=o;//line5
o=null;//line6
returnoa[0];//line7
}
}
whenisthefloatobject,createdinline3,eligibleforgarbagecollection?
publicclassx{
publicobjectm(){
objecto=newfloat(3.14f);//line3
object[]oa=newobject[1];//line4
oa[0]=o;//line5
o=null;//line6
returnoa[0];//line7
}
}
whenisthefloatobject,createdinline3,eligibleforgarbagecollection?
a.justafterline5.
b.justafterline6
c.justafterline7(thatis,asthemethodreturns)
d.neverinthismethod
12:
whatwillhappenwhenyouattempttocompileandrunthefollowingcode?
publicclassstatic
{
static
{
intx=5;
}
staticintx,y;
publicstaticvoidmain(stringargs[])
{
x—;
mymethod();
system.out.println(x+y+++x);
}
publicstaticvoidmymethod()
{
y=x+++++x;
}
}
choices:
whatwillhappenwhenyouattempttocompileandrunthefollowingcode?
publicclassstatic
{
static
{
intx=5;
}
staticintx,y;
publicstaticvoidmain(stringargs[])
{
x—;
mymethod();
system.out.println(x+y+++x);
}
publicstaticvoidmymethod()
{
y=x+++++x;
}
}
choices:
a.prints:
2
b.prints:
3
c.prints:
7
d.prints:
8
13:
假定a和b为int型变量,则执行下述语句组后,b的值为
a=1;
b=10;
do
{
b-=a;
a++;
}while(b—<0);
a.9
b.-2
c.-1
d.8
14:
设有变量说明语句inta=1,b=0;
则执行以下程序段的输出结果为()。
switch(a)
{
case1:
switch(b)
{
case0:
printf("**0**");break;
case1:
printf("**1**");break;
}
case2:
printf("**2**");break;
}
printf("");
a.**0**
b.**0****2**
c.**0****1****2**
d.有语法错误
15:
关于垃圾收集的哪些叙述是对的。
a.程序开发者必须自己创建一个线程进行内存释放的工作。
b.垃圾收集将检查并释放不再使用的内存。
c.垃圾收集允许程序开发者明确指定并立即释放该内存。
d.垃圾收集能够在期望的时间释放被java对象使用的内存。
简答题
16:
请设计一个java程序,程序中要进行数组操作和除法操作,要求对所设计的程序可能出现的异常进行处理。
17:
说明jsp中errorpage的作用,应用范围。
18:
在一个文件中有10g个整数,乱序排列,要求找出中位数。
内存限制为2g。
只写出思路即可。
19:
swtich是否能作用在byte上,是否能作用在long上,是否能作用在string上?
20:
请指出下面程序中的错误:
classfather
{
privateintage;
publicvoidsetage(inta)
{
this.age=a;
}
publicintgetage()
{
returnage;
}
publicvoiddisp()
{
system.out.println("ageis"+age);
}
}
classsonextendsfather
{
stringname;
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