公司笔试题-java广州java笔试题爱立信_h

1、文件Part I Single Selection (2 score per question)1.Which statement is true?( )public void test(int x) int odd = 1; if (odd) System.out.println(odd); else System.out.println(even);(A) odd will always be output.(B) even will always be output.(C) Compilation fails.(D) odd will be output for odd values o

2、f x, and even for even values.2.Which one is not valid IP address ?(A) 54 (B) 55 (C) 54 (D) 563.Select the one correct answer. The number of characters in an object of a class String is given by( )(A) The member variable called size.(B) The member variab

3、le called length(C) The method size() returns the number of characters.(D) The method length() returns the number of characters.4.Which code determines the int value data closer to, but not greater than, a double value b? ( )(A) Int data = (int) Math.floor(b);(B) Int data = (int) Math.abs(b);(C) Int

4、 data = (int) Math.ceil(b);(D) Int data = (int) Math.min(b);5.Linux file permission setting is presented by one string which length is 10,it can be divided into 4 parts from left to right, So what is the meaning of the part 3 ? Such as drwxrwxr-x = part1:d, part2:rwx, part3:rwx, part4:r-x(A) file ty

5、pe (B) permissions of file owner (C) permissions of file owners group (D) permissions of other users6.What will be the output of the program? ( )public class X public static void ma try tring args)badMethod(); System.out.print(A); catch (RuntimeException ex) System.out.print(B); catch (Exception ex1

6、) System.out.print(C); finally System.out.print(D);System.out.print(E);1文件public static void badMethod() throw new RuntimeException();(A) BD(B) BCD(C) B(D) BDE7.What is valid returnType for getData? ( )public class ReturnData getData(byte a, double z) return (a / z) * 10;(A) short(B) byte(C) int(D)

7、double8.What is the result? ( )public static void ma int index = 1;tring args)Boolean test = new Boolean3; boolean data = testindex;System.out.println(data);(A) true(B) false(C) null(D) NullPointerException9.What is the output? ( )public class Accessment implements Cloneable, Comparable int value =

8、1;public static void matring args) throws CloneNotSupportedException Accessment a = new Accessment(); Accessment b = change1(a); Accessment c = change2(b);System.out.println(a = b) + , +(a = c) + , +(b = c) + , +a.equals(c);static Accessment change2(Accessment b) throws CloneNotSupportedException Ac

9、cessment result = (Accessment) b.clone(); return result;static Accessment change1(Accessment a) a.setValue(2); return a;public void setValue(int value) this.value = value;public int compareTo(Accessment o) return this.value - o.value;public boolean equals(Object obj) return pareTo(Accessment

10、) obj) = 0;2文件(A) true,false,false,true(B) false,false,true,false(C) true,true,false,true(D) false,true,true,false10. Here is a network /24，the gateway is 。when server 0 want to communicate with network /24,which one is the right route setting:(A) route ad

11、d net gw netmask metric 1(B) route add net gw netmask 55 metric 1(C)route add net gw netmask metric 1(D) route add default netmask metric 1Part II Multiple Selection

12、(3 score per question)1. In OSI 7 layers model, which one will be included? (A) Physical Layer(B) Abstract Layer(C) Interface Layer (D) Transport Layer (E) Session Layer2. Linux is which kind of Operating System?(A) Multi User(B) Multi Tasking(C) Multi Process (D) All of the above(E) None of the abo

13、ve3.Run statements below, return false item(s) ( ) String a = hello;String b = hello;String c = new String(hello); char d = h,e,l,l,o;(A) System.out.println(a=b); (B) System.out.println(a=c);(C) System.out.println(a=d); (D)System.out.println(a.equals(d);4.The wrong statement(s) ( )(A) constructor in

14、 class cant ignore(B) constructor name must same with class name，but method name cant same with class name(C) constructor called when call object new (D) one class only has one constructor5.The method(s) in Thread class ( )(A) start()(B) run()(C) exit()(D) getPriority()6.Which of the following class

15、 belongs to the char type stream ( )(A) BufferedWriter3文件(B) FileInputStream(C) ObjectInputStream(D) InputStreamReader7.Java interface modifiers include ( )A privateB protectedC finalD abstract8.In Red hat which config file responsible for ip domain name resolution?(A) /etc/hosts(B) /etc/resolv.conf

16、(C) /etc/profile(D) /.bash_rc9.Linux command(s) for view net port used ( )(A) ping (B) netstat (C) lsof (D) ifconfig10. For a distributed computing system, the following ( ) indices cannot to satisfy together(A) consistency(B) availability(C) security(D) partition tolerancePart III Answer Question (

17、5 score per question)1. There is one HelloWorld.java (has main method) which imported some classes from lib.jar.How to compile the java file and execute the compiled class in command line? 编译：javac -Djava.ext.dirs=. HelloWorld.java 运行：java -Djava.ext.dirs=. HelloWorld2. Please fill in blank lines to

18、 finish these codes (you can write more than 1 line in each blank line if needed):./ get a loggerLogger logger = xxx;/ get one connection to databaseConnection conn = xxxx;/ create one transactionTransaction tx = xxxx;try logger.debug(“excute CRUD”); / do some CRUD works begin./ do some CRUD works e

19、nd mit(); catch (Exception e) tx rollback(); finally session.close(); 4文件.3. We has one command startEcho in linux, when execute this command it will print out hello world to console every 30 seconds. Now we want this command to be executed in background even when I logoff linux, and all the c

20、ontents it prints out should be stored in /tmp/startEcho.log.nohup hello world /tmp/startEcho.log 2&1&So how can I achieve this? (assume yourself have root account)4. There is a Java singleton example below.Please provide your codes to correct it for invoking the Singleton.get good performance.tance

21、() method in multi-thread environment withpublic class Singleton private static Singletontance = null;private Singleton() super();public static synchronized Singleton gettance() if (tance = null) tance = new Singleton();returntance;Part IV Programming (10 score per question)1. Write a multiple threa

22、d program to sum a big array. for example, use 5 threads to sum an integer array of 1 to 1000, one thread sum 200 numbers.public class MultiCalc private long totalResult = 5L;private Boolean isCompleted = null;public static void matring args) (new MultiCalc().startUp();private boolean isSuccessed()

23、for (int i = 0; i isCompleted.length; i+) if (!isCompletedi)return false;return true;private void startUp() 5文件int threadNum = 5;long numbers = 1000L;isCompleted = new BooleanthreadNum;for (int i = 1; i = threadNum; i+) isCompletedi - 1 = false;Thread t = new Thread(new CalcThread(i, numbers, thread

24、Num); t.start();synchronized (MultiCalc.this) try MultiCalc.this.wait(); catch (InterruptedException e) e.printStackTrace();System.out.println(计算结果为： + totalResult);classCalcThread implements Runnable private long start; private long end; private long result; private int threadIndex;public CalcThrea

25、d(int threadIndex, long numbers, int threadNum)long step = numbers / threadNum; this.threadIndex =threadIndex; start = (threadIndex - 1) * step + 1;if (threadIndex = threadNum) / 是否是最后一个线程end = numbers; else end = threadIndex * step;Overridepublic void run() for (long i = start; i = 60 for those les

26、son id = 3.SELECT *FROM STUDENT WHERE SCORE =60 AND LESSON =3Write a SQL to find out the average score for each student for his all lessons;2.SELECT NAME AVG(SCORE) FROM STUDENT GROUP BY NAME3.Write a SQL to find out the student whose score is larger than the average of each lesson and sort by LESSO

27、N (first) and NAME (second). (5 score)7文件SELECT LESSON NAME SCORE FROM (SELECT LESSON AVG(SCORE) A FROM STUDENT GROUP BY LESSON),STUDENT WHERE SCORE A;Part V English Writing (10 score)Scenario:1.2.Your English name is Kim.You are in a team name “GoodTeam”, and the team is doing some outsource projects for customer named “IT corpora