2024年Java認(rèn)證筆試歷年真題薈萃含答案

2024年Java認(rèn)證筆試歷年真題薈萃含答案（圖片大小可自由調(diào)整）第1卷一.參考題庫(共30題)1.11.?double?input?=?314159.26；? 12.?NumberFormat?nf=?NumberFormat.getInstance（Locale.ITALIAN）；? 13.?String?b；? 14.?//insert?code?here? Which?code，?inserted?at?line?14，?sets?the?value?of?b?to?3?14.159，26？（）?A、?b?=?nf.parse（?input）；B、?b?=?nf.format（?input）；C、?b?=?nf.equals（?input）；D、?b?=?nf.parseObject（?input）；2. And?MainClass?exists?in?the?/apps/com/company/application?directory.?Assume?the?CLASSPATH?environment?variable?is?set?to?"."?（current?directory）.Which?two?java?commands?entered?at?the?command?line?will?run?MainClass？（）A、java?MainClass?if?run?from?the?/apps?directoryB、java?pany.application.MainClass?if?run?from?the?/apps?directoryC、java?-classpath?/apps?pany.application.MainClass?if?run?from?any?directoryD、java-classpath?.?MainClass?if?run?from?the?/apps/com/company/application?directoryE、java?-classpath?/apps/com/company/application：.?MainClass?if?run?from?the?/apps?directoryF、java?pany.application.MainClass?if?run?from?the?/apps/com/company/application?directory3.Given?an?HttpServlet?Request?request?and?Http?Servlet?Response?response，?which?sets?a?cookie?“username”?with?the?value?“joe”?in?a?servlet.？（）A、?request.add?Cookie?（“username”.?“joe”）B、?request.set?Cookie?（“username，?“joe”）C、?response.add?Cookie?（username”，?“joe”））D、?request.add?Header?（new?Cookie?（“username”，?“joe”））E、?request.add?Cookie?（new?Cookie?（“username”，?“joe”））F、?response.add?Cookie?（new?Cookie?（“username”，?“joe”））G、?response.add?Header?（new?Cookie?（“username”，?“joe”））4.有關(guān)new關(guān)鍵字的描述正確的是哪項(xiàng)？（）?????A、創(chuàng)建對象實(shí)例的時(shí)候可以不使用new關(guān)鍵字B、new所創(chuàng)建的對象不占用內(nèi)存空間C、new會調(diào)用類的構(gòu)造器來創(chuàng)建對象D、new所創(chuàng)建的對象一定存在引用變量5.現(xiàn)有：? class??Test4??{? public?static?void?main?（String??[]??args）??{??? boolean?X=true；?? boolean?y=false；??? short?Z=42；??? if（（z++==42）??＆＆??（y=true））z++；??? if（（x=false）??||????（++z==45））??z++；??? System.?out.println（¨z=”+z）；??? ?}??? }? 結(jié)果為：（）?A、??Z=42B、??z=44C、??Z=?45D、??z=?466.1.?class?Calc?{? 2.?public?static?void?main（String?[]?args）?{? 3.?try?{? 4.?int?x?=?Integer.parseInt（"42a"）；? 5.?//insert?code?here? 6.?System.out.print（"oops?"）；? 7.?}? 8.?}? 9.?}? 下面哪兩行分別插入到第五行，會導(dǎo)致輸出“oops”？（）A、}?catch?（ClassCastException?c）?{B、}?catch?（IllegalStateException?c）?{C、}?catch?（NumberFormatException?n）?{D、}?catch?（IllegalArgumentException?e）?{7. For?a?given?product?instance，?which?three?jsp：setProperty?attributes?must?be?used?to?initialized?its?properties?form?the?HTML?form？?（）A、?idB、?nameC、?typeD、?paramE、?propertyF、?reqParamG、?attribute8.public?void?test（int?x）?{? int?odd?=?x%2；? if?（odd）?{? ?System.out.println（“odd）；? }?else?{? System.out.println（“even”）；? }? }? Which?statement?is?true？（）?A、Compilation?fails.B、?“odd”?will?always?be?output.C、?“even”?will?always?be?output.D、?“odd”?will?be?output?for?odd?values?of?x，?and?“even”?for?even?values.E、?“even”?will?be?output?for?add?values?of?x，?and?“odd”?for?even?values.9.java接口的方法修飾符可以為（）。（忽略內(nèi)部接口）A、privateB、protectedC、finalD、abstract10.現(xiàn)有? import?java.io.PrintWriter；????? class??DoFormat{? public??static?void?main?（String??[]??args）??{????? int?x=42；? int?y=12345；???? float?Z-7?；? System.out.format（"一%4d-"，??X）； System.?out.format（"-%4d-"，??y）；???? System.?out.format（"-%4.ld-"，z）；????? }????? }????? 結(jié)果為：（）?????A、編譯失敗B、??-42-??-1234-?-7.0-C、?-?42-?-1234-?-7.0-D、?-?42-?-12345-?-7.0-E、運(yùn)行時(shí)異常被拋出11.public?class?Test?{? public?static?void?main（String?[]?args）?{? boolean?assert?=?true；? if（assert）?{? System.out.println（”assert?is?true”）；? }? }? } Given：? javac?-source?1.3?Test.java? What?is?the?result？（）?A、?Compilation?fails.B、?Compilation?succeeds?with?errors.C、?Compilation?succeeds?with?warnings.D、?Compilation?succeeds?without?warnings?or?errors.12.You?are?developing?several?tag?libraries?that?will?be?sold?for?development?of?third-party?web?applications.You?are?about?to?publish?the?first?three?libraries?as?JAR?files：?container-tags.jar，advanced-html-form-tags.jar，?and?basic-html-form-tags.jar. Which?two?techniques?are?appropriate?for?packaging?the?TLD?files?forthese?tag?libraries？（）A、The?TLD?must?be?located?within?the?WEB-INF?directory?of?the?JAR?file.B、The?TLD?must?be?located?within?the?META-INF?directory?of?the?JAR?file.C、The?TLD?must?be?located?within?the?META-INF/tld/?directory?of?the?JAR?file.D、The?TLD?must?be?located?within?a?subdirectory?of?WEB-INF?directory?of?the?JAR?file.E、The?TLD?must?be?located?within?a?subdirectory?of?META-INF?directory?of?the?JAR?file.13.AnInterface?is?an?interface.?? AnAdapter0?is?a?non-abstract，?non-final?class?with?a?zero?argument?constructor.?? AnAdapter1?is?a?non-abstract，?non-final?class?without?a?zero?argument?constructor，?but?with?a?constructor?that?takes?one?int?argument.??? Which?two?construct?an?anonymous?inner?class？（）???A、AnAdapter1?aa=new?AnAdapter1（）{}B、AnAdapter0?aa=new?AnAdapter0（）{}C、AnAdapter0?aa=new?AnAdapter0（5）{}D、AnAdapter1?aa=new?AnAdapter1（5）{}E、AnInterface?a1=new?AnInterface（5）{}14.現(xiàn)有：?? class?Thread2?implements?Runnable?{?? void?run（）?{?? System.out.print（"go?"）；?? }?? public?static?void?main（String?[]?args）?{?? Thread2?t2?=?new?Thread2（）；?? Thread?t?=?new?Thread（t2）；?? t.start（）；?? }?? }?? 結(jié)果為：（）A、?goB、?編譯失敗C、?代碼運(yùn)行，無輸出結(jié)果D、?運(yùn)行時(shí)異常被拋出15.You?have?created?a?servlet?that?generates?weather?maps.?The?data?for?these?maps?is?calculated?by?aremote?host.?The?IP?address?of?this?host?is?usually?stable，?but?occasionally?does?have?to?change?as?thecorporate?network?grows?and?changes.?This?IP?address?used?to?be?hard?coded，?but?after?the?fifth?change?tothe?IP?address?in?two?years，?you?have?decided?that?this?value?should?be?declared?in?the?deploymentdescriptor?so?you?do?NOT?have?the?recompile?the?web?application?every?time?the?IP?address?changes. Which?deployment?descriptor?snippet?accomplishes?this?goal？（）A、B、C、D、16.子類可以繼承父類的除私有成員以外的其它所有成員。17.A?JSP?page?needs?to?set?the?property?of?a?given?JavaBean?to?a?value?that?is?calculated?with?the?JSP?page. Which?three?jsp：setProperty?attributes?must?be?used?to?perform?this?initialization？（）A、IdB、ValC、NameD、ParamE、ValueF、Property18.11.classSnoochy{ 12.Boochybooch； 13.publicSnoochy（）{booch=newBoochy（this）；} 14.} 15. 16.classBoochy{ 17.Snoochysnooch； 18.publicBoochy（Snoochys）{snooch=s；} 19.} Andthestatements： 21.publicstaticvoidmain（String[]args）{ 22.Snoochysnoog=newSnoochy（）； 23.snoog=null； 24.//morecodehere 25.} Whichstatementistrueabouttheobjectsreferencedbysnoog，snooch，andboochimmediatelyafterline23executes？（）A、Noneoftheseobjectsareeligibleforgarbagecollection.B、Onlytheobjectreferencedbyboochiseligibleforgarbagecollection.C、Onlytheobjectreferencedbysnoogiseligibleforgarbagecollection.D、Onlytheobjectreferencedbysnoochiseligibleforgarbagecollection.E、Theobjectsreferencedbysnoochandboochareeligibleforgarbagecollection.19.Which?four?statments?are?true？（） A、Raccoon?is-a?Mammal.B、Raccoon?has-a?Mammal.C、BabyRaccoon?is-a?Mammal.D、BabyRaccoon?is-a?Raccoon.E、BabyRaccoon?has-a?Mammal.F、BabyRaccoon?is-a?BabyRaccoon.20.將一個(gè)正整數(shù)分解質(zhì)因數(shù)。例如：輸入90，打印出90=2*3*3*5。 程序分析：對n進(jìn)行分解質(zhì)因數(shù)，應(yīng)先找到一個(gè)最小的質(zhì)數(shù)k，然后按下述步驟完成：???? （1）如果這個(gè)質(zhì)數(shù)恰等于n，則說明分解質(zhì)因數(shù)的過程已經(jīng)結(jié)束，打印出即可。???? （2）如果n??k，但n能被k整除，則應(yīng)打印出k的值，并用n除以k的商，作為新的正整數(shù)你n，重復(fù)執(zhí)行第一步。???? （3）如果n不能被k整除，則用k+1作為k的值，重復(fù)執(zhí)行第一步。21.選出不正確的敘述（）。A、死鎖是指因相互競爭資源使得系統(tǒng)中有多個(gè)阻塞進(jìn)程的情況B、若系統(tǒng)中并發(fā)運(yùn)行的進(jìn)程和資源之間滿足互斥條件、占有且申請、不可搶占和環(huán)路條件，則可判定系統(tǒng)中發(fā)生了死鎖C、在對付死鎖的策略中，解除死鎖通常都是和檢測死鎖配套使用D、產(chǎn)生死鎖的原因可歸結(jié)為競爭資源和進(jìn)程推進(jìn)順序不當(dāng)E、在死鎖的解決方法中，由于避免死鎖采用靜態(tài)分配資源策略，所以對資源的利用率不高22.11.publicstaticvoidmain（String[]args）{ 12.Objectobj=newint[]{1，2，3}； 13.int[]someArray=（int[]）obj； 14.for（inti：someArray）System.out.print（i+""） 15.} Whatistheresult？（）A、123B、Compilationfailsbecauseofanerrorinline12.C、Compilationfailsbecauseofanerrorinline13.D、Compilationfailsbecauseofanerrorinline14.E、AClassCastExceptionisthrownatruntime.23.設(shè)有方法： 則b可以為（）A、nullB、b的類型為AC、b的類型為A的子類D、b的類型為A的父類24.以下涉及到內(nèi)存管理的代碼段中，有錯(cuò)誤的是：（）。 A、AB、BC、CD、D25.A?developer?wants?a?web?application?to?be?notified?when?the?application?is?about?to?be?shut?down. Whichtwo?actions?are?necessary?to?accomplish?this?goal？（）A、Include?a?listener?directive?in?a?JSP?pageB、configure?a?listener?in?the?TLD?file?using?the??elementC、Include?a??element?in?the?web?application?deployment?descriptorD、configure?a?listener?in?the?application?deployment?descriptor，?using?the??elementE、Include?a?class?implementing?ServletContextListener?as?part?of?the?web?application?deploymen26.運(yùn)行時(shí)，數(shù)組以哪種方式存在？（）??A、對象?B、基本類型變量?C、引用類型變量?D、視具體情況而定27.以下哪個(gè)不是Collection的子接口（）A、?ListB、?SetC、?MapD、?SortedSet28.線程安全的map在JDK1.5及其更高版本環(huán)境有哪幾種方法可以實(shí)現(xiàn)（）。A、Map?map?=?new?HashMap（）B、Map?map?=?new?TreeMap（）C、Map?map?=?new?ConcurrentHashMap（）D、Map?map?=?Collections.synchronizedMap（new?HashMap（））29.interface?Altitude?{? //insert?code?here?? }?? 和4個(gè)聲明：?? int?HIGH?=?7；? public?int?HIGH?=?7；??? abstract?int?HIGH?=?7；?? interface?int?HIGH?=?7；? 分別插入到第2行，有多少行可以編譯？（）??A、?0B、?1C、?2D、?3E、?430.A?developer?is?designing?the?presentation?tier?for?a?web?application?that?relies?on?a?complex?session?bean.The?session?bean?is?still?being?developed?and?the?APIs?for?it?are?NOT?finalized.?Any?changes?to?the?sessionbean?API?directly?impacts?the?development?of?the?presentation?tier.? Which?design?pattern?provides?a?meansto?manage?the?uncertainty?in?the?API？（）A、View?HelperB、Front?ControllerC、Composite?ViewD、Intercepting?FilterE、Business?Delegate第1卷參考答案一.參考題庫1.參考答案:B2.參考答案:B,C3.參考答案:F4.參考答案:C5.參考答案:D6.參考答案:C,D7.參考答案:A,D,G8.參考答案:A9.參考答案:D10.參考答案:E11.參考答案:C12.參考答案:B,E13.參考答案:B,D14.參考答案:B15.參考答案:D16.參考答案:正確17.參考答案:C,E,F18.參考答案:E19.參考答案:A,B,C,F20.參考答案:21.參考答案:A,B22.參考答案:A23.參考答案:A,B,C24.參考答案:A,B,D25.參考答案:D,E26.參考答案:A27.參考答案:C28.參考答案:C,D29.參考答案:C30.參考答案:E第2卷一.參考題庫(共30題)1.如何引用包中的某個(gè)類？如何引用整個(gè)包？如果編寫JavaApplet程序時(shí)想把整個(gè)java．a(chǎn)pplet包都加載，則應(yīng)該怎么做？2.javax.swing.Timer將按一定頻率產(chǎn)生什么事件（）A、ActionEventB、TimerEventC、ItemEventD、InputEvent3.Click?the?’Select?and?Place’?button. Place?the?events?in?the?order?they?occur. 4.Which?is?a?benefit?of?precompiling?a?JSP?page？（）A、It?avoids?initialization?on?the?first?request.B、It?provides?the?ability?to?debug?runtime?errors?in?the?application.C、It?provides?better?performance?on?the?first?request?for?the?JSP?page.D、It?avoids?execution?of?the?_jspService?method?on?the?first?request.5.For?which?three?events?can?web?application?event?listeners?be?registered？（）A、When?a?session?is?createdB、After?a?servlet?is?destroyedC、When?a?session?has?timed?outD、When?a?cookie?has?been?createdE、When?a?servlet?has?forwarded?a?requestF、When?a?session?attribute?value?is?changed6.現(xiàn)有：D?? -?f?是一個(gè)對?java.io.File?實(shí)例的合法引用?? -?fw?是一個(gè)對?java.io.FileWriter?實(shí)例的合法引用?? -?bw?是一個(gè)對?java.io.BufferedWriter?實(shí)例的合法引用?? 以下哪一項(xiàng)無效？（）??A、?PrintWriter?prtWtr?＝?new?PrintWriter（f）；B、?PrintWriter?prtWtr?＝?new?PrintWriter（fw）；C、?PrintWriter?prtWtr?＝?new?PrintWriter（bw）；D、?BufferWriter?bufWtr?＝?new?BufferedWriter（f）；E、?BufferWriter?bufWtr?＝?new?BufferedWriter（fw）；F、?BufferWriter?bufWtr?＝?new?BufferedWriter（bw）；7.實(shí)例方法是根據(jù)引用變量的聲明類型進(jìn)行訪問的8.A?developer?for?the?C?web?site?has?been?told?that?users?may?turn?off?cookie?support?in?their?browsers.?What?must?the?developer?do?to?ensure?that?these?customers?can?still?use?the?web?application？（）??A、?The?developer?must?ensure?that?every?URL?is?properly?encoded?using?the?appropriate?URL?rewriting?APIsB、?The?developer?must?provide?an?alternate?mechanism?for?managing?sessions?and?abandon?theHttpSession?mechanism?entirelyC、?The?developer?can?ignore?this?issue.?Web?containers?are?required?to?support?automatic?URL?rewriting?when?cookies?are?not?supportedD、?The?developer?must?ass?the?string?？id=?to?the?end?of?every?URL?to?ensure?that?the?conversion?with?the?browser?can?continue.9.You?are?writing?a?JSP?that?includes?scriptlet?code?to?declare?a?List?variable?and?initializes?that?variable?to?anArrayList?object. Which?two?JSP?code?snippets?can?you?use?to?import?these?list?types？（）A、B、C、D、E、F、10.拍七游戲打印出"拍七"游戲規(guī)則：大家依次從1開始順序數(shù)數(shù)，數(shù)到含有7或7的倍數(shù)的要拍手或其它規(guī)定的方式表示越過（比如：7，14，17等都不能數(shù)出），下一人繼續(xù)數(shù)下面的數(shù)字。違反規(guī)則者受罰。11.HTTP中的POST和GET在下列哪些方面有區(qū)別（）。A、數(shù)據(jù)位置B、明文密文C、數(shù)據(jù)安全D、長度限度E、應(yīng)用場景12.求四位的水仙花數(shù)。即滿足這樣條樣的四位數(shù)：各位數(shù)字的4次方和等于該數(shù)自身。13.窗口監(jiān)聽器有哪些特點(diǎn)？（）A、可以繼承窗口適配器（WindowAdapter）類，并覆寫其中需要用到的函數(shù)B、窗口監(jiān)聽器所實(shí)現(xiàn)的接口是WindowListener，它有多？個(gè)函數(shù)C、窗口監(jiān)聽器可以只實(shí)現(xiàn)WindowListener接口中的一兩個(gè)函數(shù)D、響應(yīng)窗口打開，關(guān)閉，最小化成圖標(biāo)，由圖標(biāo)還原，激活，無效，最大化，還原，獲取焦點(diǎn)，失去作業(yè)點(diǎn)等事件E、僅在Windows操作系統(tǒng)下有效14.下面哪個(gè)類不能直接讀取磁盤文件（）A、FileReaderB、RandomAccessFileC、FilterReaderD、FileInputStream15.1.?int?I=1，?j=0? 2.??? 3.?switch（i）??{? 4.?case?2：? 5.?j+=6；? 6.??? 7.?case?4：? 8.?j+=1；? 9.??? 10.?default：? 11.?j?+=2；? 12.??? 13.?case?0：? 14.?j?+=4；? 15.?}? 16.????? What?is?the?value?of?j?at?line?16？（）A、?0B、?1C、?2D、?4E、?616.Which?four?are?true？（）A、?Has-a?relationships?should?never?be?encapsulated.B、?Has-a?relationships?should?be?implemented?using?inheritance.C、?Has-a?relationships?can?be?implemented?using?instance?variables.D、?Is-a?relationships?can?be?implemented?using?the?extends?keyword.E、?Is-a?relationships?can?be?implemented?using?the?implements?keyword.F、?An?array?or?a?collection?can?be?used?to?implement?a?one-to-many?has-a?relationship.G、?The?relationship?between?Movie?and?Actress?is?an?example?of?an?is-a?relationship.17.內(nèi)存垃圾回收將刪除無法訪問的對象18.What?is?the?result？（） A、Compilation?fails.B、Cannot?add?ToppingsC、The?code?runs?with?no?output.D、A?NullPointerException?is?thrown?in?Line?14.19.What?will?be?written?to?the?standard?output?when?the?following?program?is?run？（）?? public?class?Q8499?{?? public?static?void?main（String?args[]）?{? double?d?=?-2.9；?? int?i?=?（int）?d；? i?*=?（int）?Math.ceil（d）；? i?*=?（int）?Math.abs（d）；?? System.out.println（i）；? ?}? ?}A、12B、18C、8D、9E、2720.為將數(shù)組myArray的長度由6改為10，現(xiàn)采取以下編碼：? int[]?myArray?=?new?int[6]；? myArray?=?new?int[10]；?? 代碼執(zhí)行后，以下敘述哪項(xiàng)是正確的？（）?A、?數(shù)組myArray的長度已由6改為10，其中前6個(gè)元素的值不變，后四個(gè)元素的值為空。B、?數(shù)組myArray的長度已由6改為10，其中前6個(gè)元素的值不變，后四個(gè)元素需再經(jīng)過初始化后才能使用。C、?數(shù)組myArray的長度已由6改為10，原來6個(gè)元素的值全部丟失。D、?數(shù)組myArray的長度沒有變化。21.public?class?Threads2?implements?Runnable?{? public?void?nun（）?{? System.out.println（”run.”）；? throw?new?RuntimeException（”Problem”）；? }? public?static?void?main（String[]?args）?{? Thread?t?=?new?Thread（new?Threads2（））；? t.start（）；? System.out.println（”End?of?method.”）；? }? }? Which?two?can?be?results？（）A、?java.lang.RuntimeException：?ProblemB、?run.

java.lang.RuntimeException：?ProblemC、?End?of?method.

java.lang.RuntimeException：?ProblemD、?End?of?method.?

run.

java.lang.RuntimeException：?ProblemE、?run.

java.lang.RuntimeException：?Problem?

End?of?method.22.java中，用（）關(guān)鍵字定義常量。A、finalB、#defineC、floatD、const23.A?C?developer?is?designing?the?presentation?tier?for?a?web?application?that?relies?on?a?complex?session?bean.?The?session?bean?is?still?being?developed?and?the?APIs?for?are?NOT?finalized.?Any?changes?to?the?session?bean?API?directly?impacts?the?development?of?the?presentation?tier.? Which?design?pattern?provides?a?means?to?manage?the?uncertainty?in?the?API？（）A、?View?HelperB、?Front?ControllerC、?Composite?ViewD、?Intercepti