JAVA程序员笔试题目与答案.docx

1、JAVA程序员笔试题目与答案JAVA程序员笔试题目与答案1. Given: Integeri=newInteger(42); Longl=newLong(42); Doubled=newDouble(42.0); WhichtwoexpressionsevaluatetoTrue? A.(i=1) B.(i=d) C.(d=1) D.(i.equals(l) E.(d.equals(l) F.(i.equals(42) G.noneofabove Answer: 2.Given: publicclassFoo publicstaticvoidmain(Stringargs) StringBuf

2、fera=newStringBuffer(A); StringBufferb=newStringBuffer(B); operate(a,b); System.out.println(a+,+b); staticvoidoperate(StringBufferx,StringBuffery) x.append(y); y=x; Whatistheresult? A.Thecodecompilesandprints“A,B”. B.Thecodecompilesandprints“A,A”. C.Thecodecompilesandprints“B,B”. D.Thecodecompilesan

3、dprints“AB,B”. E.Thecodecompilesandprints“AB,AB”. F.Thecodedoesnotcompilebecause“+”cannotbeoverloadedforStringBuffer. Answer: 3.Given: classBaseClass privatefloatx=1.0f; protectedfloatgetVar()returnx; classSubclassextendsBaseClass privatefloatx=2.0f; /inserthere Whichtwoarevalidexamplesofmethodoverr

4、iding? A.floatgetVar()returnx; B.publicfloatgetVar()returnx; C.publicdoublegetVar()returnx; D.protectedfloatgetVar()returnx; E.publicfloatgetVar(floatf)returnf; Answer: 4.WhichofthefollowingaremethodsoftheRunnableinterface A)run B)start C)yield D)stop Answer: 5.Whichofthefollowingarelegalstatements?

5、 A)floatf=1/3; B)inti=1/3; C)floatf=1.01; D)doubled=999d; Answer: 6.Given: publicclasstest( publicstaticvoidmain(stringargs) Stringfoo=args1; Stringbaz=args2; Stringbax=args3; Andthecommandlineinvocation: JavaTestredgreenblue Whatistheresult? A.bazhasthevalueof“” B.bazhasthevalueofnull C.bazhastheva

6、lueof“red” D.bazhasthevalueof“blue” E.baxhasthevalueof“green” F.thecodedoesnotcompile G.theprogramthrowsanexception Answer: 7.Whichofthefollowingstatementsaretrue? A)ThegarbagecollectionalgorithminJavaisvendorimplemented B)Thesizeofprimitivesisplatformdependent C)Thedefaulttypeforanumericalliteralwi

7、thdecimalcomponentisafloat. D)YoucanmodifythevalueinanInstanceoftheIntegerclasswiththesetValuemethod Answer: 8.Given: inti=1,j=10; do if(i+-j)continue; while(i5); Afterexecution,whatarethevaluesforiandj? A.i=6andj=5 B.i=5andj=5 C.i=6andj=4 D.i=5andj=6 E.i=6andj=6 Answer: 9.Given: importjava.io.IOExc

8、eption; publicclassExceptionTest publicstaticvoidmain(Stringargs) try methodA(); catch(IOExceptione) System.out.println(CaughtIOException); catch(Exceptione) System.out.println(CaughtException); publicvoidmethodA() thrownewIOException(); Whatistheresult? A.Thecodewillnotcompile. B.Theoutputis:caught

9、exception. C.Theoutputis:caughtIOException. D.Theprogramexecutesnormallywithoutprintingamessage. Answer: 10.Given: publicclassTest publicstaticStringoutput=; publicstaticvoidfoo(inti) try if(i=1) thrownewException(); output+=1; catch(Exceptione) output+=2; return; finally output+=3; output+=4; publi

10、cstaticvoidmain(Stringargs) foo(0); foo(1); /line24 Whatisthevalueofthevariableoutputatline24? Answer: 11.Given: publicclassFooimplementsRunnable/line1 publicvoidrun(Threadt)/line2 System.out.println(Running.); publicstaticvoidmain(Stringargs) newThread(newFoo().start(); Whatistheresult? A.Anexcepti

11、onisthrown B.Theprogramexistswithoutprintinganything C.Anerroratline1causescompilationtofail. D.Anerroratline2causesthecompilationtofail. E.“Running”isprintedandtheprogramexits Answer: 12.Given: ClassOne.java packagecom.abc.pkg1; publicclassClassOne privatecharvar=a; chargetVar()returnvar; ClassTest

12、.java packagecom.abc.pkg2; importcom.abc.pkg1.ClassOne; publicclassClassTestextendsClassOne publicstaticvoidmain(Stringargs) chara=newClassOne().getVar();/line5 charb=newClassTest().getVar();/line6 Whatistheresult? A.Compilationwillfail. B.Compilationsucceedsandnoexceptionsarethrown. C.Compilationsu

13、cceedsbutanexceptionisthrownatline5 inClassTest.java. D.Compilationsucceedsbutanexceptionisthrownatline6 inClassTest.java. Answer: 13.Whichisavalididentifier? A.false B.default C._object D.a-class Answer: 14Ifyourunthecodebelow,whatgetsprintedout? Strings=newString(Bicycle); intiBegin=1; chariEnd=3;

14、 System.out.println(s.substring(iBegin,iEnd); A)Bic B)ic C)icy D)error:nomethodmatchingsubstring(int,char) Answer: 15Whatwillhappenwhenyouattempttocompileandrunthefollowingcode publicclassMySwitch publicstaticvoidmain(Stringargv) MySwitchms=newMySwitch(); ms.amethod(); publicvoidamethod() intk=10; s

15、witch(k) default:/Putthedefaultatthebottom,nothere System.out.println(Thisisthedefaultoutput); break; case10: System.out.println(ten); case20: System.out.println(twenty); break; A)Noneoftheseoptions B)Compiletimeerrortargetofswitchmustbeanintegraltype C)CompileandrunwithoutputThisisthedefaultoutput

16、D)Compileandrunwithoutputofthesinglelineten Answer: 第二部分：J2EE部份 1简述J2EEArchitecture。 2简述JSP在WebContainer中的生命周期。 3如何使用数据库连接池？有什么好处？ 4列举您在开发中用到的一些模式与框架。模式与框架有什么区别吗？ 5列举您知道的几种持久化技术。 6什么是SOA?WebServices与SOA有什么样的关系? 第三部分：通用知识 1简述OSI七层协议。IP/TCP/UDP/HTTP/SMTP分别属于哪一层？ 2简述TMN，TOM，eTOM,NGOSS四个模型之间的关系。 3什么是数据库

17、系统?列举几个常见的数据库系统。 4请简单描述软件开发过程的主要阶段。 5请将下面一段文字翻译成中文。 Anenterpriseservicebus(ESB)isapatternofmiddlewarethatunifiesandconnectsservices,applicationsandresourceswithinabusiness.Putanotherway,itistheframeworkwithinwhichthecapabilitiesofabusinessapplicationsaremadeavailableforreusebyotherapplicationsthroug

18、houttheorganizationandbeyond.TheESBisnotanewsoftwareproductitsanewwayoflookingathowtointegrateapplications,coordinateresourcesandmanipulateinformation.Unlikemanypreviousapproachesforconnectingdistributedapplications,forexampleRPCordistributedobjects,theESBpatternenablestheconnectionofsoftwarerunninginparallelondifferentplatforms,writtenindifferentprogramminglanguagesandusingdifferentprogrammingmodels.