java工程師面試題

西安三元數(shù)碼軟件有限公司外派JAVA軟件工程師筆試題4303返回上級目錄選擇題1:在軟件生命周期中，下列哪個說法是不準確的?A.軟件生命周期分為計劃、開發(fā)和運行三個階段B.在計劃階段要進行問題焉醛和需求分析C.在開發(fā)后期要進行編寫代碼和軟件測試D.在運行階段主要是進行軟件維護2:publicclassParent{

intchange(){…}

}

classChildextendsParent{

}

WhichmethodscanbeaddedintoclassChild?A.publicintchange(){}B.abstractintchang(){}C.privateintchange(){}D.none3:Give

the

following

method:

public

void

method(

){

String

a,b;

a=new

String(“hello

world”);

b=new

String(“game

over”);

System.out.println(a+b+”ok”);

a=null;

a=b;

System.out.println(a);

}

In

the

absence

of

compiler

optimization,

which

is

the

earliest

point

the

object

a

refered

is

definitely

elibile

to

be

garbage

collection.

A.beforeline5B.beforeline6C.beforeline7D.beforeline94:String

s=”Example

String”;Which

operation

is

not

legal?

A.inti=s.length();B.s[3]=”x”;C.Stringshort_s=s.trim();D.Stringt=”root”+s;5:關于垃圾收集的哪些敘述是對的。A.程序開發(fā)者必須自己創(chuàng)建一個線程進行內(nèi)存釋放的工作。B.垃圾收集將檢查并釋放不再使用的內(nèi)存。C.垃圾收集允許程序開發(fā)者明確指定并立即釋放該內(nèi)存。D.垃圾收集能夠在期望的時間釋放被java對象使用的內(nèi)存。6:Give

the

following

code:

public

class

Example{

public

static

void

main(String

args[]

){

int

l=0;

do{

System.out.println(“Doing

it

for

l

is:”+l);

}while(--l>0)

System.out.println(“Finish”);

}

}

Which

well

be

output:

A.Doingitforlis3B.Doingitforlis1C.Doingitforlis2D.Doingitforlis07:Whichofthefollowingstatementsaretrue?A.TheautomaticgarbagecollectionoftheJVMpreventsprogramsfromeverrunningoutofmemoryB.AprogramcansuggestthatgarbagecollectionbeperformedandforceitC.GarbagecollectionisplatformindependentD.Anobjectbecomeseligibleforgarbagecollectionwhenallreferencesdenotingitaresettonull.8:下面關于變量及其范圍的陳述哪些是錯的。A.實例變量是類的成員變量。B.實例變量用關鍵字static聲明。C.在方法中定義的局部變量在該方法被執(zhí)行時創(chuàng)建D.局部變量在使用前必須被初始化。9:Which

is

the

most

appropriate

code

snippet

that

can

be

inserted

at

line

18

in

the

following

code?

(Assume

that

the

code

is

compiled

and

run

with

assertions

enabled)

1.

import

java.util.*;

2.

3.

public

class

AssertTest

4.

{

5.

private

HashMap

cctld;

6.

7.

public

AssertTest()

8.

{

9.

cctld

=

new

HashMap();

10.

cctld.put("in",

"India");

11.

cctld.put("uk",

"United

Kingdom");

12.

cctld.put("au",

"Australia");

13.

//

more

code...

14.

}

15.

//

other

methods

16.

public

String

getCountry(String

countryCode)

17.

{

18.

//

What

should

be

inserted

here?

19.

String

country

=

(String)cctld.get(countryCode);

20.

return

country;

21.

}

22.

}

A.assertcountryCode!=null;B.assertcountryCode!=null:"Countrycodecannotbenull";C.assertcctld!=null:"Nocountrycodedataisavailable";D.assertcctld:"Nocountrycodedataisavailable";10:在下述選項時,沒有構成死循環(huán)的程序是A.inti=100while(1){i=i%100+1;if(i>100)break;}B.for(;;);C.intk=1000;do{++k;}while(k>=10000);D.ints=36;while(s);--s;11:給出下面的代碼片斷。。。下面的哪些陳述為錯誤的?

1)

public

void

create()

{

2)

Vector

myVect;

3)

myVect

=

new

Vector();

4)

}

A.第二行的聲明不會為變量myVect分配內(nèi)存空間。B.第二行語句創(chuàng)建一個Vector類對象。C.第三行語句創(chuàng)建一個Vector類對象。D.第三行語句為一個Vector類對象分配內(nèi)存空間12:Aclassdesignrequiresthatamembervariableshouldbeaccessibleonlybysamepackage,whichmodiferwordshouldbeused?A.protectedB.publicC.nomodiferD.private13:Give

the

following

java

source

fragement:

//point

x

public

class

Interesting{

//do

something

}

Which

statement

is

correctly

Java

syntax

at

point

x?

A.publicclassMyClass{//dootherthing…}B.staticintPI=3.14C.classMyClass{//dosomething…}D.none14:WhichfragmentsarenotcorrectinJavasourcefile?A.packagetestpackage;publicclassTest{//dosomething...}B.importjava.io.*;packagetestpackage;publicclassTest{//dosomething...}C.importjava.io.*;classPerson{//dosomething...}publicclassTest{//dosomething...}D.importjava.io.*;importjava.awt.*;publicclassTest{//dosomething...}15:以下的C程序代碼片段運行后C和d的值分別是多少

Inta=1,b=2;

Intc,d;

c=(a&b)&&a;

d=(a&&b)&a;A.0,0B.0,1C.1,0D.1,116:What

will

be

the

result

of

executing

the

following

code?

public

static

void

main(String

args[])

{

char

digit

=

'a';

for

(int

i

=

0;

i

<

10;

i++)

{

switch

(digit)

{

case

'x'

:

{

int

j

=

0;

System.out.println(j);

}

default

:

{

int

j

=

100;

System.out.println(j);

}

}

}

int

i

=

j;

System.out.println(i);

}

Choices:

A.100willbeprinted11times.B.Thecodewillnotcompilebecausethevariableicannotbedeclaredtwicewithinthemain()method.C.Thecodewillnotcompilebecausethevariablejcannotbedeclaredtwicewithintheswitchstatement.D.Noneofthese.17:Give

this

class

outline:

class

Example{

private

int

x;

//rest

of

class

body…

}

Assuming

that

x

invoked

by

the

code

java

Example,

which

statement

can

made

x

be

directly

accessible

in

main()

method

of

Example.java?

A.ChangeprivateintxtopublicintxB.changeprivateintxtostaticintxC.ChangeprivateintxtoprotectedintxD.changeprivateintxtofinalintx18:WhicharenotJavakeywords?A.TRUEB.constC.superD.void19:設有變量說明語句inta=1,b=0;

則執(zhí)行以下程序段的輸出結果為（）。

switch(a)

{

case1:

switch(b)

{

case0:printf("**0**");break;

case1:printf("**1**");break;

}

case2:printf("**2**");break;

}

printf("\n");A.**0**B.**0****2**C.**0****1****2**D.有語法錯誤20:軟件生命周期的瀑布模型把軟件項目分為3個階段、8個子階段，以下哪一個是正常的開發(fā)順序?A.計劃階段、開發(fā)階段、運行階段B.設計階段、開發(fā)階段、編碼階段C.設計階段、編碼階段、維護階段D.計劃階段、編碼階段、測試階段21:What

will

happen

when

you

attempt

to

compile

and

run

the

following

code?

class

Base

{

int

i

=

99;

public

void

amethod()

{

System.out.println("Base.amethod()");

}

Base()

{

amethod();

}

}

public

class

Derived

extends

Base

{

int

i

=

-1;

public

static

void

main(String

argv[])

{

Base

b

=

new

Derived();

System.out.println(b.i);

b.amethod();

}

public

void

amethod()