2024年計(jì)算機(jī)考試-Java認(rèn)證筆試考試歷年高頻考點(diǎn)試題摘選含答案

2024年計(jì)算機(jī)考試-Java認(rèn)證筆試考試歷年高頻考點(diǎn)試題摘選含答案第1卷一.參考題庫(kù)(共75題)1.What?writes?the?text?“?”?to?the?end?of?the?file?“file.txt”？（）A、?OutputStream?out=?new?FileOutputStream?（“file.txt”）；??

Out.writeBytes?（“?/n”）；B、?OutputStream?os=?new?FileOutputStream?（“file.txt”，?true）；??

DataOutputStream?out?=?new?DataOutputStream（os）；??out.writeBytes?（“?/n”）；C、?OutputStream?os=?new?FileOutputStream?（“file.txt”）；??

DataOutputStream?out?=?new?DataOutputStream（os）；??out.writeBytes?（“?/n”）；D、?OutputStream?os=?new?OutputStream?（“file.txt”，?true）；?

?DataOutputStream?out?=?new?DataOutputStream（os）；??out.writeBytes?（“?/n”）；2.編寫(xiě)一個(gè)Java程序，接受用戶(hù)輸入的一個(gè)l-12之間的整數(shù)（如果輸入的數(shù)據(jù)不滿(mǎn)足這個(gè)條件，則要求用戶(hù)重新輸入），利用switch語(yǔ)句輸出對(duì)應(yīng)月份的天數(shù)。3.public?class?AssertStuff?{? public?static?void?main（String?[]?args）?{? int?x=?5；? int?y=?7；? assert?（x>?y）：?“stuff”；? System.out.println（”passed”）；? }? }? And?these?command?line?invocations：java?AssertStuff?java?-ea?AssertStuff?What?is?the?result？（）A、?passed?stuffB、?stuff?passedC、?passed?

An?AssertionError?is?thrown?with?the?word?“stuff”?added?to?the?stack?trace.D、?passed?

An?AssertionError?is?thrown?without?the?word?“stuff”?added?to?the?stack?trace.E、?passed?

An?AssertionException?is?thrown?with?the?word?“stuff”?added?to?the?stack?trace.F、?passed

?An?AssertionException?is?thrown?without?the?word?“stuff”?added?to?the?stack?trace.4.What?is?the?result？（） A、CatB、DogC、Compilation?fails.D、The?code?runs?with?no?output.E、An?exception?is?thrown?at?runtime.5.5.?String?foo?=?“base”；? 6.?foo.substring（0，3）；? 7.?foo.concat（“ket”）? 8.???? Type?the?value?of?foo?at?line?8.（）6.應(yīng)用FileInputStream類(lèi)，編寫(xiě)應(yīng)用程序，從磁盤(pán)上讀取一個(gè)Java程序，并將源程序代碼顯示在屏幕上。（被讀取的文件路徑為：E:///myjava/Hello.java）7.企業(yè)發(fā)放的獎(jiǎng)金根據(jù)利潤(rùn)提成。利潤(rùn)（I）低于或等于10萬(wàn)元時(shí)，獎(jiǎng)金可提10%；利潤(rùn)高于10萬(wàn)元，低于20萬(wàn)元時(shí)，低于10萬(wàn)元的部分按10%提成，高于10萬(wàn)元的部分，可可提成7.5%；20萬(wàn)到40萬(wàn)之間時(shí)，高于20萬(wàn)元的部分，可提成5%；40萬(wàn)到60萬(wàn)之間時(shí)高于40萬(wàn)元的部分，可提成3%；60萬(wàn)到100萬(wàn)之間時(shí)，高于60萬(wàn)元的部分，可提成1.5%，高于100萬(wàn)元時(shí)，超過(guò)100萬(wàn)元的部分按1%提成，從鍵盤(pán)輸入當(dāng)月利潤(rùn)，求應(yīng)發(fā)放獎(jiǎng)金總數(shù)？8.1.?class?Alpha?{?void?m1（）?{}?}?? 2.?class?Beta?extends?Alpha?{?void?m2（）?{?}?}?? 3.?class?Gamma?extends?Beta?{?}?? 4.?? 5.?class?GreekTest?{?? 6.?public?static?void?main（String?[]?args）?{?? 7.?a?Alpha?[]?a?=?{new?Alpha（），?new?Beta（），?new?Gamma（）?}；?? 8.?for（Alpha?a2?：?a）?{?? 9.?a2.m1（）；?? 10.?if?（a2?instanceof?Beta?||?a2?instanceof?Gamma）?? 11.?//insert?code?here?? 12.?}?? 13.?}?? 14.?}?? 哪一行代碼插入到第11行，將編譯但是會(huì)在運(yùn)行時(shí)產(chǎn)生異常？（）??A、?a2.m2（）；B、?（（Beta）a2）.m2（）；C、?（（Alpha）a2）.m2（）；D、?（（Gamma）a2）.m2（）；9.int?i?=?1，j?=?10；? do{? if?（i>j）?{? continue；? }? j--；? }?while?（++i?A、?i?=?6?and?j?=?5B、?i?=?5?and?j?=?5C、?i?=?6?and?j?=?4D、?i?=?5?and?j?=?6E、?i?=?6?and?j?=?610.Which?two?CANNOT?directly?cause?a?thread?to?stop?executing？?（）??A、?Existing?from?a?synchronized?block.B、?Calling?the?wait?method?on?an?object.C、?Calling?notify?method?on?an?object.D、?Calling?read?method?on?an?InputStream?object.E、?Calling?the?SetPriority?method?on?a?Thread?object.11.宴會(huì)上一共有1225次握手，設(shè)每一位參加宴會(huì)的人對(duì)其他與會(huì)人士都有一樣的禮節(jié)，那么與會(huì)人士有多少人？12.以下關(guān)于中斷控制語(yǔ)句的描述，錯(cuò)誤的是（）A、?return用于退出整個(gè)子程序B、?continue停止繼續(xù)執(zhí)行下面的語(yǔ)句，直接跳回循環(huán)起始位置C、?break用于強(qiáng)行退出循環(huán)，不執(zhí)行循環(huán)中剩余的語(yǔ)句D、?break語(yǔ)句用于中斷當(dāng)前的程序塊，如for循環(huán)塊，if結(jié)構(gòu)塊等的執(zhí)行E、?在一個(gè)函數(shù)中，不管有沒(méi)有返回值，都需要return語(yǔ)句來(lái)推出函數(shù)13.如何設(shè)置表格型布局方式？（）A、創(chuàng)建一個(gè)表格型布局管理器B、在構(gòu)造函數(shù)中指定表格的行數(shù)或列數(shù)C、添加組件，組件將按行逐個(gè)放到表格中D、創(chuàng)建一個(gè)表格型面板E、添加組件，需要指定組件放在表格的哪一行和哪一列14. What?is?the?output？??15.public?class?Test?{?? public?static?void?replaceJ（string?text）?{?? text.replace?（‘j‘，?‘l‘）；?? }?? public?static?void?main（String?args）?{?? string?text?=?new?String?（“java”）?? replaceJ（text）；?? system.out.printIn（text）；?? }?? }?? What?is?the?result？（）??A、?The?program?prints?“l(fā)ava”B、?The?program?prints?“java”C、?An?error?at?line?7?causes?compilation?to?fail.D、?Compilation?succeeds?but?the?program?throws?an?exception.16.public?class?Team?extends?java.util.LinkedList?{? public?void?addPlayer（Player?p）?{? add（p）；? }? public?void?compete（Team?opponent）?{?/*?more?code?here?*/?}? }? class?Player?{?/*?more?code?here?*/?}? Which?two?are?true？（）A、?This?code?will?compile.B、?This?code?demonstrates?proper?design?of?an?is-a?relationship.C、?This?code?demonstrates?proper?design?of?a?has-a?relationship.D、?A?Java?programmer?using?the?Team?class?could?remove?Player?objects?from?a?Team?object.17.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、18.求一個(gè)3*3矩陣對(duì)角線(xiàn)元素之和.19.有工人，農(nóng)民，教師，科學(xué)家，服務(wù)生，其中，工人，農(nóng)民，服務(wù)生只有基本工資.教師除基本工資外，還有課酬（元/天），科學(xué)家除基本工資外，還有年終獎(jiǎng)，請(qǐng)你寫(xiě)出相關(guān)類(lèi)，將各種類(lèi)型的員工的全年工資打印出來(lái)20.class?java?{? public?static?void?main（String?[]?java）?{?? for?（int?Java?=?1；?Java?〈?java.length；?Java++）?? System.out.print（"java?"）；?? }?? }?? 和命令行：? java?java?java?java?java?? 結(jié)果為：（）??A、javaB、java?javaC、java?java?javaD、編譯失敗21.結(jié)構(gòu)化程序設(shè)計(jì)有哪三種基本流程？分別對(duì)應(yīng)Java中的哪些語(yǔ)句？22.流式布局的常用設(shè)置參數(shù)有哪些？（）??A、設(shè)置組件間的水平間隙和垂直間隙B、設(shè)置每行最多放幾個(gè)組件C、設(shè)置行對(duì)齊方式D、設(shè)置組件最多可以分幾列放E、設(shè)置面板的最大尺寸和最小尺寸23.What?is?the?result？（） A、w-fB、f-p，w-fC、w-f，b-fD、f-p，w-f?b-fE、Compilation?fails.F、An?exception?is?thrown?at?runtime.24.A?developer?wants?to?make?a?name?attribute?available?to?all?servlets?associated?with?a?particular?user，across?multiple?requests?from?that?user，?from?the?same?browser?instance. Which?two?provide?this?capabilityfrom?within?a?tag?handler？（）A、pageContext.setAttribute（"name"，?theValue）B、pageContext.setAttribute（"name"，?getSession（））C、pageContext.getRequest（）.setAttribute（"name"，?theValue）D、pageContext.getSession（）.setAttribute（"name"，?theValue）E、pageContext.setAttribute（"name"，?theValue，PageContext.PAGE_SCOPE）F、pageContext.setAttribute（"name"，?theValue，PageContext.SESSION_SCOPE）25.Which?two?directives?are?applicable?only?to?tag?files？（）A、TagB、PageC、TaglibD、IncludeE、Variable26.Java語(yǔ)言中表達(dá)式“11”+22的結(jié)果是哪項(xiàng)？（）??A、33B、1122C、22D、表達(dá)式錯(cuò)誤27.已知： 的輸出為（）A、aB、bC、cD、null28.假如我們想要對(duì)象eh來(lái)處理TextArea對(duì)象t的TextEvent事件，那么我們應(yīng)如何把eh添加為t的事件處理程序？（）?????A、??t.addTextListener?（eh）B、??eh.addTextListener?（t）C、??addTextListener?（eh，t）D、??addTextListener?（t，?eh）29. Which?EL?expression，?inserted?at?line?3?is?valid?and?evaluated?to?“beanValue”？（）A、?${bean}B、?${value}C、?${beanValue}D、?${com.example.bean}E、?${requestScope[“com.example.bean”]}F、?${request.get（“com.example.bean”）.toString（）}30.現(xiàn)有：? 3．??import?java.util.*；????? 4．????class?ForInTest??{? 5.static?List?list=new?ArrayList（）；???? 6．? 7.public?static?void?main?（String??[]??args）??{???? 8.list.?add（"a"）；?list.?add（"b"）；list.?add（?"c"）；??? 9．????//insert?code?here???? 10.????System.out.print?（o）；??? 11.????}???? 12．??}? 哪一行插入到第9行將導(dǎo)致輸出“abc"？（）?A、??for?（Iterator?o??：??list.iterator（）；??o.hasNext??（）；??）B、??for?（Iterator?0??：??list）C、??for?（Object?o??：??list.iterator（））D、??for?（Object?o??：??list）31.某試卷由26個(gè)問(wèn)題組成，答對(duì)一題得8分，答錯(cuò)一題扣5分。今有一考生雖然回答了全部26個(gè)問(wèn)題，但所得總分為零，問(wèn)他錯(cuò)答多少題。32.Given：? 8.int?index?=?1：? 9.Boolean?[]?test?=?new?boolcan?[3]；? 10.boolcan?foo?=?test?[index]；?? What?is?the?result（）？??A、?foo?has?the?value?of?0.B、?foo?has?the?value?of?null.C、?foo?has?the?value?of?true.D、?foo?has?the?value?of?false.E、?An-exception?is?thrown.F、?The?code?will?not?compile.33.Aprogrammerneedstocreatealoggingmethodthatcanacceptanarbitrarynumberofarguments.Forexample，itmaybecalledintheseways： logIt（"logmessage1"）； logIt（"logmessage2”，”logmessage3"）； logIt（"logmessage4"，"logmessage5"，"logmessage6"）； Whichdeclarationsatisfiesthisrequirement（）？A、publicvoidlogIt（String*msgs）B、publicvoidlogIt（String[]msgs）C、publicvoidlogIt（String...msgs）D、publicvoidlogIt（Stringmsg1，Stringmsg2，Stringmsg3）34.10.?public?class?MyClass?{? 11.? 12.?public?Integer?startingI；? 13.?public?void?methodA（）?{? 14.?Integer?i?=?new?Integer（25）；? 15.?startingI?=?i；? 16.?methodB（i）；? 17.?}? 18.?private?void?methodB（Integer?i2）?{? 19.?i2?=?Value（）；? 20.? 21.?}? 22.?}? If?methodA?is?invoked，?which?two?are?true?at?line?20？（）A、?i2?==?startingI?returns?true.B、?i2?==?startingI?returns?false.C、?i2.equals（startingI）?returns?true.D、?i2.equals（startingI）?returns?false.35.class?Flibitz{?? public?static?void?main（String[]?args）{?? int?grop=7；?? new?Flibitz（）.go（grop）；?? System.out.print（grop）；? }?? void?go（int?grop）{?? if（++grop>7）?grop++；?? System.out.print（grop）；?? }?? } 結(jié)果為：（）??A、99B、編譯失敗C、運(yùn)行時(shí)異常被拋出D、77E、79F、9736.Given?the?web?application?deployment?descriptor?elements： 11. 12.ParamAdder 13.com.example.ParamAdder 14 24. 25.ParamAdder 26.MyServlet 27. 28. Which?element，?inserted?at?line?27，causes?the?ParamAdder?filter?to?be?applied?when?MyServlet?is?invokedby?another?servlet?using?the?RequestDispatcher.include?method？（）A、B、INCLUDEC、includeD、INCLUDEE、include37.You?have?been?contracted?to?create?a?web?site?for?a?free?dating?service.?One?feature?is?the?ability?for?oneclient?to?send?a?message?to?another?client，?which?is?displayed?in?the?latter?client’s?private?page.?Yourcontract?explicitly?states?that?security?is?a?high?priority.?Therefore，?you?need?to?prevent?cross-site?hacking?inwhich?one?user?inserts?JavaScript?code?that?is?then?rendered?and?invoked?when?another?user?views?thatcontent. Which?two?JSTL?code?snippets?will?prevent?cross?site?hacking?in?the?scenario?above？?（）A、${message}B、C、D、${message}E、38.class?TestApp{?? public?static?void?main?（String[?]?args）{?? for（int?i=0；iA、0123B、012C、0123456789D、01245678939.如何暫停一個(gè)線(xiàn)程？（）A、?調(diào)用System.pauseThred函數(shù)暫停B、?調(diào)用線(xiàn)程類(lèi)的pauseThred函數(shù)暫停C、?調(diào)用Runnable接口的pauseThread函數(shù)暫停D、?調(diào)用Thred類(lèi)的sleep靜態(tài)函數(shù)暫停線(xiàn)程40.一輛以固定速度行駛的汽車(chē)，司機(jī)看到里程表上從左到右的讀數(shù)和從右到左的讀數(shù)是相同的，這個(gè)數(shù)是12321（公里），2小時(shí)后，里程表上再次出現(xiàn)一個(gè)新的對(duì)稱(chēng)數(shù)。問(wèn)車(chē)的速度是多少公里/小時(shí)？41.t?是一個(gè)合法的?Thread?對(duì)象的引用，并且?t?的合法?run（）?方法如下：? public?void?run（）?{? System.out.print（"go?"）；? }? 及：?? t.start（）；? t.start（）；? t.run（）；? 哪一個(gè)是結(jié)果？（）?A、goB、go?goC、go?go?goD、go?之后跟著一個(gè)異常42.Java源文件的后綴名是？（）??A、.classB、.cC、.javaD、.txt43.int?i?=?0，?j?=?1；? if?（（i++?==?1）?&&?（j++?==?2））?{? i?=?42；? }? System.out.println（“i?=?“?+?i?+?“，?j?=?“?+?j）；?? What?is?the?result？（）??A、?i?=?1，?j?=?2B、?i?=?1，?j?=?1C、?i?=?42，?j?=?2D、?i?=?42，?j?=?1E、?Compilation?fails.44.輸出流輸出數(shù)據(jù)后，應(yīng)調(diào)用哪個(gè)方法將其關(guān)閉？（）?A、stop（）B、flush（）C、exit（）D、close（）45.One?of?the?use?cases?in?your?web?application?uses?many?session-scoped?attributes.?At?the?end?of?the?usecase，?you?want?to?clear?out?this?set?of?attributes?from?the?session?object.?Assume?that?this?static?variableholds?this?set?of?attribute?names： 201.private?static?final?Set?USE_CASE_ATTRS；? 202.static?{ 203.USE_CASE_ATTRS.add（"customerOID"）； 204.USE_CASE_ATTRS.add（"custMgrBean"）； 205.USE_CASE_ATTRS.add（"orderOID"）； 206.USE_CASE_ATTRS.add（"orderMgrBean"）； 207.} Which?code?snippet?deletes?these?attributes?from?the?session?object？（）A、session.removeAll（USE_CASE_ATTRS）；B、for（?String?attr?：?USE_CASE_ATTRS?）{?session.remove（attr）；?}C、for（?String?attr?：?USE_CASE_ATTRS?）{session.removeAttribute（attr）；}D、for（?String?attr?：?USE_CASE_ATTRS?）{session.deleteAttribute（attr）；}E、session.deleteAllAttributes（USE_CASE_ATTRS）；46.現(xiàn)有：? int?x?＝?reader.read（）；?? 下面哪一項(xiàng)正確？（）??A、?閱讀器可以是FileReader或者BufferedReaderB、?閱讀器不是FileReader或者BufferedReader類(lèi)型C、?閱讀器可以是FileReader類(lèi)型，但不能是BufferedReader類(lèi)型D、?閱讀器可以是BufferedReader類(lèi)型，但不能是FileReader類(lèi)型47.Which?is?a?valid?identifier？（）??A、?falseB、?defaultC、?_objectD、?a-class48. What?is?the?result（）？A、?Compilation?will?succeed.B、?Compilation?will?fail?at?line?5.C、?Compilation?will?fail?at?line?6.D、?Compilation?will?fail?at?line?14.E、?Compilation?will?fail?at?line?17.49.如何定義繼承關(guān)系？為“學(xué)生”類(lèi)派生出“小學(xué)生”、“中學(xué)生”、“大學(xué)生”、“研究生”四個(gè)類(lèi)，其中“大學(xué)生”類(lèi)再派生出“一年級(jí)學(xué)生”、二年級(jí)學(xué)生”、“三年級(jí)學(xué)生”、“四年級(jí)學(xué)生”四個(gè)子類(lèi)，“研究生”類(lèi)再派生出“碩士生’’和“博土生’’兩個(gè)子類(lèi)。50.已知： 在橫線(xiàn)處添加哪條語(yǔ)句運(yùn)行時(shí)會(huì)產(chǎn)生異常（）A、Aa=b；B、Ii=b；C、Cc=（C）b；D、Bd=（B）（A）b；51.簡(jiǎn)單變量和引用變量在作為類(lèi)的成員這是時(shí)，有什么區(qū)別（）??A、簡(jiǎn)單成員變量不需要初始化，引用變量需要在構(gòu)造函數(shù)中初始化B、引用成員變量不需要初始化，簡(jiǎn)單成員變量需要在構(gòu)造函數(shù)中初始化C、類(lèi)的成員變量可以自動(dòng)初始化，因此沒(méi)有區(qū)別D、簡(jiǎn)單成員變量會(huì)自動(dòng)初始化為默認(rèn)值（0），而引用變量只會(huì)自動(dòng)初始化為空值，實(shí)際使用時(shí)還需要將它指向一個(gè)對(duì)象52.What?is?the?result？（） A、Compilation?fails?because?of?an?error?in?line?3.B、Compilation?fails?because?of?an?error?in?line?7.C、Compilation?fails?because?of?an?error?in?line?9.D、If?you?define?D?e?=?new?E（），then?e.bMethod（）?invokes?the?version?of?bMethod（）?defined?in?Line?5.E、If?you?define?D?e?=?（D）（new?E（）），then?e.bMethod（）?invokes?the?version?of?bMethod（）?defined?in?Line?5.F、If?you?define?D?e?=?（D）（new?E（）），then?e.bMethod（）?invokes?the?version?of?bMethod（）?defined?in?Line?9.53.int?x=?10；? do?{? x--；? }?while（xA、?ten?timesB、?zero?timesC、?one?to?me?timesD、?more?than?ten?times54.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?changed55.Which?two?prevent?a?servlet?from?handling?requests.？（）A、?The?servlet’s?init?method?returns?a?non-zero?status.B、?The?servlet’s?init?method?throws?a?Servlet?ExceptionC、?The?servlet’s?init?method?sets?the?Servlet?Response’s?context?length?to?0D、?The?servlet’s?init?method?sets?the?Servlet?Response’s?content?type?to?null.E、?The?servlet’s?init?method?does?NOT?return?within?a?time?period?defined?by?the?servletcontainer.56.求三位數(shù)中，個(gè)位數(shù)字與十位數(shù)字之和除以10所得的余數(shù)是百位數(shù)字，且百位數(shù)字是偶數(shù)的數(shù)的個(gè)數(shù)。57.Which?statement?of?assigning?a?long?type?variable?to?a?hexadecimal?value?is?correct？（）A、?long?number?=?345L；B、?long?number?=?0345；C、?long?number?=?0345L；D、?long?number?=?0x345L；58.Which?thetwo?are?concerning?the?objects?available?to?developers?creating?tag?files？（）A、?The?session?object?must?be?declared?explicity.B、?The?request?and?response?objects?are?available?implicity.C、?The?output?stream?is?available?through?the?implicit?outStream?object.D、?The?servlet?context?is?available?through?the?implicit?servletContext?object.E、?The?JspContext?for?the?tag?file?is?available?through?the?implicit?jspContext?object.59.Click?the?'Select?and?Place'?button. Place?the?events?in?the?order?they?occur. 60.Which?three?are?valid?URL?mappings?to?a?servlet?in?a?web?deployment?descriptor？?（）A、?*/*B、?/*.doC、?myServletD、?/MyservletE、?/MyServlet/*F、?MyServlet/*.isp61.現(xiàn)有如下類(lèi)型：????? a?-?java.util.Hashtable????? b?-?java.util.List????? c?-?java.util.ArrayList????? d?-?java.util.SortedSet????? 和定義：????? 1-使用本接口，允許用戶(hù)控制集合中每個(gè)元素的插入位置。????? 2-使用本集合，確保用戶(hù)可以按照遞增或元素的自然順序遍歷集合。????? 3-本具體類(lèi)型允許空元素及基于索引的訪問(wèn)。????? 4-本集合是同步的。????? 哪一組匹配是對(duì)的？（）?????A、2描述d；??3描述b。B、1描述b；??3描述c。C、3描述a；??4描述b。D、4描述a；??2描述c。62.11.?double?d?=?Math.random（）；?? Which?is?true?about?d?after?line?11？（）??A、?d?>=?1.0B、?0.0?63.求數(shù)列2，4，8，16，32，…前若干項(xiàng)之和。當(dāng)和大于9000時(shí)，終止求和并輸出結(jié)果64.在類(lèi)Acoount中，正確引入類(lèi)school.Student的語(yǔ)句是哪一項(xiàng)？（）??A、import?schoolB、import?schllo.*C、package?school.StudentD、import?Student65.Which?two?demonstrate?encapsulation?of?data？?（）A、?Member?data?have?no?access?modifiers.B、?Member?data?can?be?modified?directly.C、?The?access?modifier?for?methods?is?protected.D、?The?access?modifier?to?member?data?is?private.E、?Methods?provide?for?access?and?modification?of?data.66.Click?the?Exhibit?button. The?h：highlight?tag?renders?its?body，?highlighting?an?arbitrary?number?of?words，?each?of?which?is?passed?asan?attribute?（word1，?word2，?...）.?For?example，?a?JSP?page?can?invoke?theh：highlight?tag?as?follows： 11.? 12.?high?medium?low 13.? Given?that?HighlightTag?extends?SimpleTagSupport，which?three?steps?are?necessary?to?implement?the?taghandler?for?the?highlight?tag？（）A、Add?a?doTag?methodB、Add?a?doStartTag?methodC、Add?a?getter?and?setter?for?the?color?attributeD、Create?and?implement?a?TagExtraInfo?classE、Implement?the?DynamicAttributes?interfaceF、Add?a?getter?and?setter?for?the?word1?and?word2?attributes67.public?class?SyncTest?{? private?int?x；?? private?int?y；?? public?synchronized?void?setX?（int?i）?（x=1；）?? public?synchronized?void?setY?（int?i）?（y=1；）?? public?synchronized?void?setXY（int?1）（set?X（i）；?setY（i）；）?? public?synchronized?Boolean?check（）?（return?x?!=y；）?? }?? Under?which?conditions?will?check?（）?return?true?when?called?from?a?different?class？?A、?Check（）?can?never?return?true.B、?Check（）?can?return?true?when?setXY?is?called?by?multiple?threads.C、?Check（）?can?return?true?when?multiple?threads?call?setX?and?setY?separately.D、?Check（）?can?only?return?true?if?SyncTest?is?changed?to?allow?x?and?y?to?be?set?separately.68.程序：? class??TestApp{? public?static?void?main（String[]?args）{? System.out.println（multiply（2，3，4，5））；? }? public?int?multiply（int[]?nums）{?????? int?result?=?1；?????? for（int?x?：nums）?????????? result?*=?x；?????? return?result；???}?}? 程序運(yùn)行后的輸出是哪項(xiàng)？（）?A、?14B、?編譯錯(cuò)誤C、?120D、?2469.What?is?the?result？（） A、0B、1C、4D、Compilation?fails.E、An?exception?is?thrown?at?runtime.70.怎樣進(jìn)行文件及目錄的管理？71.Which?two?JSTL?URL-related?tags?perform?URL?rewriting？（）A、UrlB、LinkC、ParamD、ImportE、Redirect72.public?class?Yippee2?{? static?public?void?main（String?[]?yahoo）?{? for（int?x=?1；?xSystem.out.print（yahoo[x]?+?“?“）；? }? }? }? and?the?command?line?invocation：?java?Yippee2?a?b?c?What?is?the?result？（）? A、a?bB、b?cC、a?b?cD、?Compilation?fails.E、?An?exception?is?thrown?at?runtime.73.Which?code，?inserted?at?line?14，?sets?the?value?of?b?to?314.159，26？（） A、b=nf.parse（input）；B、b=nf.format（input）；C、b=nf.equals（input）；D、b=nf.parseObject（input）；74.設(shè)計(jì)一個(gè)圓類(lèi)，將圓的位置（圓心坐標(biāo)和半徑）作為屬性（提供任意圓的設(shè)置），并能計(jì)算圓的面積。75.Given： 3.class?MyServlet?extends?HttpServlet?{ 4.public?void?doPut（HttpServletRequest?req，?HttpServletResponse?resp）?throws?ServletException，IOException?{ 5.//?servlet?code?here?... 26.} 27.} If?the?DD?contains?a?single?security?constraint?associated?with?MyServlet?and?its?only??tagsand??tags?are：GETPUT Admin Which?four?requests?would?be?allowed?by?the?container？（）A、A?user?whose?role?is?Admin?can?perform?a?PUT.B、A?user?whose?role?is?Admin?can?perform?a?GET.C、A?user?whose?role?is?Admin?can?perform?a?POST.D、A?user?whose?role?is?Member?can?perform?a?PUT.E、A?user?whose?role?is?Member?can?perform?a?POST.F、A?user?whose?role?is?Member?can?perform?a?GET.第2卷一.參考題庫(kù)(共75題)1.1.?class?Pizza?{? 2.?java.util.ArrayList?toppings；? 3.?public?final?void?addTopping（String?topping）?{? 4.?toppings.add（topping）； 5.?}? 6.?}? 7.?public?class?PepperoniPizza?extends?Pizza?{? 8.?public?void?addTopping（String?topping）?{? 9.?System.out.println（”Cannot?add?Toppings”）；? 10.?}? 11.?public?static?void?main（String[]?args）?{? 12.?Pizza?pizza?=?new?PepperoniPizza（）；? 13.?pizza.addTopping（”Mushrooms”）；? 14.?}? 15.?}? What?is?the?result？（）?A、?Compilation?fails.B、?Cannot?add?ToppingsC、?The?code?runs?with?no?output.D、?A?NullPointerException?is?thrown?in?Line?4.2.class?MyApp{?? public?static?void?main（String[]?args）{??int?age；?? System.out.println（“age=”+age）；??}??}?? 執(zhí)行上述代碼后輸出的結(jié)果是哪項(xiàng)？（）??A、age=0B、age=nullC、age=D、程序編譯錯(cuò)誤3.Use?the?operators?""，?which?statements?are?true？?（）???A、?0000?0100?0000?0000?0000?0000?0000?0000>5?gives????1111?1110?0000?0000?0000?0000?0000?0000D、?1100?0000?0000?0000?0000?0000?0000?0000>>5?gives????0000?0110?0000?0000?0000?0000?0000?00004.利用Applet類(lèi)和Runnable接口實(shí)現(xiàn)滾動(dòng)字幕，其中字幕文字（“學(xué)好Java有工作”）和時(shí)間間隔（“200”）需要由頁(yè)面文件中標(biāo)記的子標(biāo)記傳遞。5.Upon?a?user’s?first?visit?to?the?website，?which?two?operations?are?always?performed?when?the?getSession?method?is?called?with?no?arguments?in?a?servlet？（）A、?All?URLs?returned?by?the?server?are?rewritten.B、?An?HttpSession?object?is?created?if?necessary.C、?The?user?name?and?password?of?the?user?are?checked.D、?The?session?ID?is?stored?in?the?HTTP?response?as?a?cookie.6.public?class?Test?{? public?static?void?main（String?[]?args）?{? int?x?=5；? boolean?b1?=?true；? boolean?b2?=?false；? if（（x==4）?&&?!b2）? System.out.print（”l?“）；? System.out.print（”2?“）；? if?（（b2?=?true）?&&?b1）? System.out.print（”3?“）；? } }? What?is?the?result？（）?A、?2B、?3C、?1?2D、?2?3E、?1?2?3F、?Compilation?fails.G、?Au?exceptional?is?thrown?at?runtime.7.Which?statement?is?true?about?the?class?of?an?object?that?can?reference?the?variable?base？（） A、It?can?be?any?class.B、No?class?has?access?to?base.C、The?class?must?belong?to?the?geometry?package.D、The?class?must?be?a?subclass?of?the?class?Hypotenuse.8.1.?import?java.util.*；? 2.?public?class?TestSet?{? 3.?enum?Example?{?ONE，?TWO，?THREE?}? 4.?public?static?void?main（String[]?args）?{? 5.?Collection?coll?=?new?ArrayList（）；? 6.?coll.add（Example.THREE）；? 7.?coll.add（Example.THREE）；? 8.?coll.add（Example.THREE）；? 9.?coll.add（Example.TWO）；? 10.?coll.add（Example.TWO）；? 11.?coll.add（Example.ONE）；? 12.?Set?set?=?new?HashSet（coll）；? 13.?}? 14.?}? Which?statement?is?true?about?the?set?variable?on?line?12？（）?A、?The?set?variable?contains?all?six?elements?from?the?coll?collection，?and?the?order?is?guaranteed?to?be?preserved.B、?The?set?variable?contains?only?three?elements?from?the?coll?collection，?and?the?order?is?guaranteed?to?be?preserved.C、?The?set?variable?contains?all?six?elements?from?the?coil?collection，?but?the?order?is?NOT?guaranteed?to?be?preserved.D、?The?set?variable?contains?only?three?elements?from?the?coil?collection，?but?the?order?is?NOT?guaranteed?to?be?preserved.9.A?programmer?has?an?algorithm?that?requires?a?java.util.List?that?provides?an?efficient?implementation?of?add（0，object），?but?does?NOT?need?to?support?quick?random?access.?What?supports?these?requirements？（）?A、?java.util.QueueB、?java.util.ArrayListC、?java.util.LinearListD、?java.util.LinkedList10.public?class?Foo?{? public?void?main（?String[]?args?）?{? System.out.println（?“Hello”?+?args[0]?）；? }? }?? What?is?the?result?if?this?code?is?executed?with?the?command?line？（）A、?HelloB、?Hello?FooC、?Hello?worldD、?Compilation?fails.E、?The?code?does?not?run.11.Which?statement?is?true？（） A、Compilation?succeeds.B、class?A?does?not?compile.C、The?method?declared?on?line?9?cannot?be?modified?to?throw?TestException.D、TestA?compiles?if?line?10?is?enclosed?in?try/catch?block?that?catches?TestException.12.以下函數(shù)中，不是Object類(lèi)所有的是（）?A、notifyB、valueOfC、toStringD、wait13.程序員想要?jiǎng)?chuàng)建一個(gè)名為MyThread的類(lèi)以便在main方法中用Thread實(shí)例化。對(duì)于下面三行：? MyThread必須繼承Thread。????? MyThread必須實(shí)現(xiàn)Thread。? MyThread必須覆蓋public?void?run（）。 有幾行是正確的（）?A、?0B、?1C、?2D、?314.What?is?the?output？（） A、42B、420C、462D、4204215.Given?a?correctly?compiled?class?whose?source?code?is：? package?com.sun.sjcp；? public?class?Commander?{? public?static?void?main（String[]?args）?{? //?more?code?here? }? }? Assume?that?the?class?file?is?located?in?/foo/com/sun/sjcp/，?the?current?directory?is?/foo/，?and?that?the?classpath?contains?“.“?（current?directory）.?Which?command?line?correctly?runs?Commander？（）?A、?java?CommanderB、?java?com.?sim.?sjcp.CommanderC、?java?com/sun/sjcp/CommanderD、?java?-cp?com.sun.sjcp?CommanderE、?java?-cp?com/sun/sjcp?Commander16.Applet的布局設(shè)置默認(rèn)是FlowLayout，F(xiàn)列哪項(xiàng)代碼可以改變Applet的布局方式？?（）A、??setLayoutManager（new?GridLayout（））；B、??setLayout?（new?GridLayout（2，2））；C、??setGridLayout?（2，2）；D、??setBorderLayout（）；17.package?geometry；? public?class?Hypotenuse?{? public?InnerTriangle?it?=?new?InnerTriangle（）；? class?InnerTriangle?{? public?int?base；? public?int?height；? }? }? Which?is?true?about?the?class?of?an?object?that?can?reference?the?variable?base？?（）A、?It?can?be?any?class.B、?No?class?has?access?to?base.C、?The?class?must?belong?to?the?geometry?package.D、?The?class?must?be?a?subclass?of?the?class?Hypotenuse.18.求1～200之間勾股數(shù)的組數(shù)（如a*a+b*b=c*c，則a，b，c為一組勾股數(shù)）19.現(xiàn)有：? class?Wrench?f? public?static?void?main（String??[]??args）??{? Wrench?w=new?Wrench（）；????Wrench?w2=new?Wrench（）；???? w2=go?（w，?w2）；????? System.out.print?（w2==w）；????? }? static?Wrench?go?（Wrench?wrl，??Wrench?wr2）??{???? Wrench?wr3=wrl；?wrl=wr2；?wr2=wr3；???? return?wr3；????? }?????? 結(jié)果是什么？（）?????A、?falseB、?trueC、編譯失敗D、運(yùn)行的時(shí)候有異常拋出20.接口中只能包含抽象方法，不能包含實(shí)例方法21.Which?three?code?fragments，?added?individually?at?line?29，?produce?the?output?100？（） A、n?=?100；B、i.setX（100）；C、o.getY（）.setX（100）；D、i?=?new?Inner（）；?i.setX（100）；E、o.setY（i）；?i?=?new?Inner（）；?i.setX（100）；F、i?=?new?Inner（）；?i.setX（100）；?o.setY（i）；22. Which?two?are?true（）A、?Line?13?is?not?valid?for?a?servlet?declarationB、?Line?14?is?not?valid?for?a?servlet?declarationC、?One?instance?of?the?servlet?will?be?loaded?at?startupD、?Ten?instance?of?the?servlet?will?be?loaded?at?start?upE、?the?servlet?will?be?referenced?by?the?name?catalog?in?mappings23.class?Flow?{? public?static?void?main（String?[]?args）?{? try?{? System.out.print（"before?"）；? doRiskyThing（）；? System.out.print（"after?"）；? }?catch?（Exception?fe）?{? System.out.print（"catch?"）；? }? System.out.println（"done?"）；? }? ?public?static?void?doRiskyThing（）?throws?Exception?{? //?this?code?returns?unless?it?throws?an?Exception? }?}? 可能會(huì)產(chǎn)生下面哪兩項(xiàng)結(jié)果？（）?A、beforeB、before?catchC、before?after?