java軟件工程師面試題及答案英語

一、單項選擇題（每題2分，共20分）

1.WhichofthefollowingisnotaprimitivedatatypeinJava?

A.int

B.String

C.double

D.boolean

2.WhatisthedefaultaccessmodifierforaclassmemberinJava?

A.public

B.private

C.protected

D.default(package-private)

3.WhichofthefollowingisnotacollectionframeworkinterfaceinJava?

A.List

B.Set

C.Map

D.Stream

4.Whatistheoutputofthefollowingcodesnippet?

```java

Strings="Hello";

s=s.substring(1);

System.out.println(s);

```

A.Hello

B.ello

C.He

D.ello

5.WhatisthecorrectwaytodeclareavariableinJava?

A.intnumber;

B.numberint;

C.intnumber=0;

D.BothAandC

6.WhichofthefollowingisnotavalidJavaoperator?

A.+=

B.&&

C.||

D.++

7.Whatisthepurposeofthe'synchronized'keywordinJava?

A.Toincreasetheperformanceofthecode

B.Toensurethatamethodorblockofcodeisexecutedbyonlyonethreadatatime

C.Toallowmultiplethreadstoexecutethesamemethodsimultaneously

D.Tostopathreadfromexecuting

8.Whatistheoutputofthefollowingcodesnippet?

```java

booleanflag=true;

if(flag=false){

System.out.println("Flagisfalse");

}else{

System.out.println("Flagistrue");

}

```

A.Flagisfalse

B.Flagistrue

C.Compilationerror

D.Runtimeerror

9.WhichofthefollowingisnotavalidJavaexceptionhandlingkeyword?

A.try

B.catch

C.finally

D.end

10.Whatisthepurposeofthe'final'keywordinJava?

A.Todeclareamethodthatcannotbeoverridden

B.Todeclareaclassthatcannotbeextended

C.Todeclareavariablewhosevaluecannotbechangedafterinitialization

D.Alloftheabove

答案：

1.B

2.D

3.D

4.B

5.D

6.D

7.B

8.B

9.D

10.D

二、多項選擇題（每題2分，共20分）

1.WhichofthefollowingaretrueaboutJava?

A.Javaisplatform-independent.

B.Javaisacompiledlanguage.

C.Javasupportsmultipleinheritance.

D.Javasupportsgarbagecollection.

2.WhichofthefollowingarevalidwaystocreateanewthreadinJava?

A.ByextendingThreadclassandoverridingitsrun()method.

B.ByimplementingRunnableinterfaceandpassingittoThreadconstructor.

C.ByusingtheExecutorServiceinterface.

D.ByusingtheForkJoinPoolclass.

3.WhichofthefollowingareconsideredasbestpracticesinJavaprogramming?

A.Usingmeaningfulvariablenames.

B.Avoidingmagicnumbers.

C.Commentingeverylineofcode.

D.FollowingtheDRY(Don'tRepeatYourself)principle.

4.WhichofthefollowingarevalidwaystohandleexceptionsinJava?

A.Usingtry-catchblocks.

B.Usingtry-finallyblocks.

C.Usingtry-with-resources.

D.Ignoringexceptions.

5.WhichofthefollowingaretrueaboutJavagenerics?

A.Theyprovidetypesafetyatcompiletime.

B.Theyallowforthecreationofclassesandmethodsthatcanoperateonobjectsofvarioustypeswhileprovidingcompile-timetypesafety.

C.Theyareaformoftypeerasure.

D.Theycanbeusedwithprimitivetypes.

6.WhichofthefollowingarevalidwaystodeclareandinitializeanArrayListinJava?

A.ArrayList<String>list=newArrayList<>();

B.List<String>list=newArrayList<>();

C.ArrayListlist=newArrayList<String>();

D.Listlist=newArrayList<>();

7.WhichofthefollowingarevalidJavaannotations?

A.@Override

B.@Deprecated

C.@SuppressWarnings

D.@interface

8.WhichofthefollowingaretrueaboutJavainterfaces?

A.Aninterfacecanhavedefaultmethods.

B.Aninterfacecanhavestaticmethods.

C.Aninterfacecanextendmultipleotherinterfaces.

D.Aninterfacecanhaveinstancevariables.

9.WhichofthefollowingarevalidwaystopassparameterstoamethodinJava?

A.Byvalue

B.Byreference

C.Byname

D.Byposition

10.WhichofthefollowingaretrueaboutJavalambdaexpressions?

A.Theyareusedtorepresentinstancesoffunctionalinterfaces.

B.Theycanhaveparametersandabody.

C.Theycanbeassignedtovariables.

D.TheycanbeusedwiththeStreamAPI.

答案：

1.A,B,D

2.A,B,C

3.A,B,D

4.A,B,C

5.A,B,C

6.A,B,D

7.A,B,C

8.A,B,C

9.A,B

10.A,B,D

三、判斷題（每題2分，共20分）

1.Javasupportsoperatoroverloading.(False)

2.The'this'keywordinJavacanbeusedtoreferencethecurrentobject.(True)

3.Java's'switch'statementcanonlybeusedwithstrings.(False)

4.AllexceptionsinJavaaresubclassesoftheThrowableclass.(True)

5.Java's'enum'canhavemethodsandconstructors.(True)

6.Java's'synchronized'keywordcanbeusedonmethodsandblocksofcode.(True)

7.Java's'transient'keywordisusedtoindicatethatafieldisnotserialized.(True)

8.Java's'volatile'keywordisusedtoensurethatavariableisnotcachedthread-locally.(True)

9.Java's'assert'statementisusedfordebuggingpurposes.(True)

10.Java's'const'keywordisusedtodeclareconstantvariables.(False)

答案：

1.F

2.T

3.F

4.T

5.T

6.T

7.T

8.T

9.T

10.F

四、簡答題（每題5分，共20分）

1.Whatisthedifferencebetween'==’and'equals()'inJava?

2.Explainthedifferencebetween'final','finally',and'finalize()'inJava.

3.Whatisthepurposeofthe'static'keywordinJava,andhowdoesitaffectclassmembers?

4.DescribetheprocessofgarbagecollectioninJava.

答案：

1.'=='checksforreferenceequality,comparingwhethertworeferencespointtothesameobjectinmemory.'equals()'isamethodthatcanbeoverriddentocomparetheactualcontentofobjectsforequality.

2.'final'isusedtodeclareavariablewhosevaluecannotbechanged,amethodthatcannotbeoverridden,oraclassthatcannotbeextended.'finally'isablockofcodethatisalwaysexecutedafteratry-catchblock,regardlessofwhetheranexceptionwasthrownorcaught.'finalize()'isamethodintheObjectclassthatiscalledbythegarbagecollectorjustbeforeanobjectisbeinggarbagecollected.

3.The'static'keywordisusedtodeclareclassmembersthatareassociatedwiththeclassitselfratherthaninstancesoftheclass.Staticmemberscanbeaccessedwithoutcreatinganinstanceoftheclassandaresharedamongallinstances.

4.GarbagecollectioninJavaistheprocessofautomaticallyidentifyinganddiscardingobjectsthatarenolongerinusebytheprogram,freeingupmemoryfornewobjects.

五、討論題（每題5分，共20分）

1.DiscusstheimportanceofexceptionhandlinginJavaandhowitcanimprovetherobustnessofanapplication.

2.ExplaintheroleofinterfacesinJavaandhowtheycanbeusedtoachievepolymorphism.

3.DiscussthebenefitsanddrawbacksofusingJavagenerics.

4.WhataresomebestpracticesforwritingcleanandmaintainableJavacode?

答案：

1.ExceptionhandlingiscrucialforcreatingrobustJavaapplicationsasitallowsdeveloperstoanticipateandhandleerrorsgracefully,preventingtheapplicationfro