大数据基础技能试题及答案

1、Java 基础1. Which of the following will compile correctly?A) float f=10f;B) float f=10.1;C) float f=10.1f;D) byte b=10b;2. Which declarations of identifiers are legal A. $personsB. TwoUsers C. *pointD. thisE. _endline3. Which statement of assigning a long type variable to a hexadecimal value is correc

2、tA. long number = 345L;B. long number = 0345;C. long number = 0345L;D. long number = 0x345L4. Which of the following fragments might cause errors A. String s = "Gone with the wind"String t = " good "String k = s + t;B. String s = "Gone with the wind"String t;t = s3 + &q

3、uot;one"C. String s = "Gone with the wind"String standard = s.toUpperCase();D. String s = "home directory"String t = s - "directory"5. Which are syntactically valid statement at/ point x class Person private int a;public int change(int m) return m; 精选文库public class

4、 Teacher extends Person public int b;public static void main(String arg)Person p = new Person();Teacher t = new Teacher();int i;/ point xA. i = m;B. i = b;C. i = p.a;D. i = p.change(30);E. i = t.b.6. Which layout manager is used when the frame is resized the buttons's position in the Frame might

5、 be changedA. BorderLayoutB. FlowLayoutC. CardLayoutD. GridLayout7. Given the following code fragment: 1) public void create() 2 Vector myVect;3 myVect = new Vector(); 4 Which of the following statements are trueA. The declaration on line 2 does not allocate memory space for the variable myVect.B. T

6、he declaration on line 2 allocates memory space for a reference to a Vector object.C. The statement on line 2 creates an object of class Vector.D. The statement on line 3 creates an object of class Vector.E. The statement on line 3 allocates memory space for an object of class Vector8. Which of the

7、following answer is correct to express the value 8 in octal number A. 010B. 0x10 C. 08 D. 0x89. Which are not Java keywordsA. TRUEB. sizeofC. const-2精选文库D. superE. void10. Which of the following statements are trueA. The equals() method determines if reference values refer to the same object.B. The

8、= operator determines if the contents and type of two separate objects match.C. The equals() method returns true only when the contents of two objects match.D. The class File overrides equals() to return true if the contents and type of two separate objects match.11. Which statements about inheritan

9、ce are trueA. In Java programming language only allows single inheritance.B. In Java programming language allows a class to implement only one interface.C. In Java programming language a class cannot extend a class and implement a interface together.D. In Java programming language single inheritance

10、 makes code more reliable.12.1) class Person 2 public void printValue(int i, int j) /* */ 3 public void printValue(int i)/*.*/ 4 5) public class Teacher extends Person 6 public void printValue() /*.*/ 7 public void printValue(int i) /*.*/8 public static void main(String args)9 Person t = new Teacher

11、();10 t.printValue(10);11 12 Which method will the statement on line 10 callA. on line 2B. on line 3C. on line 6D. on line 713. Which are not Java primitive types A. shortB. Boolean C. unitD. float-3精选文库14、 The method resume() is responsible for resuming which thread's execution A. The thread wh

12、ich is stopped by calling method stop()B. The thread which is stopped by calling method sleep()C. The thread which is stopped by calling method wait()D. The thread which is stopped by calling method suspend()15. Which of the following range of int is correctA. -27 27-1B. 0 232-1C. -215 215-1D. -231

13、231-116. Which keyword should be used to enable interaction with the lock of an object The flag allows exclusive access to that object.A. transientB. synchronized C. serializeD. static17. Which is the return type of the method main()A. intB. voidC. booleanD. static18. Given the following code:Which

14、range of x value would print the string "second"A. x > 0B. x > -3C. x <= -3D. x <= 0 & x > -319、 Which of the following answer is correct to express the value 10 in hexadecimal numberA. 0xAB. 0x16C. 0AD. 01620. Which statements about the garbage collection are trueA. The

15、 program developer must create a thread to be responsible for free the memory.-4精选文库B. The garbage collection will check for and free memory no longer needed. C. The garbage collection allow the program developer to explicity and immediately free the memory.D. The garbage collection can free the mem

16、ory used java object at expect time.21、 Given the following code:1) public class Test 2 int m, n;3 public Test() 4 public Test(int a) m=a; 5 public static void main(String arg) 6 Test t1,t2;7 int j,k; 8 j=0; k=0;9 t1=new Test(); 10 t2=new Test(j,k); 11 12 Which line would cause one error during comp

17、ilationA. line 3B. line 5C. line 6D. line 1022、 Given the uncompleted code of a class:class Person String name, department;int age;public Person(String n) name = n; public Person(String n, int a) name = n; age = a; public Person(String n, String d, int a) / doing the same as two arguments version of

18、 constructor/ including assignment name=n,age=adepartment = d;Which expression can be added at the "doing the same as." part of the constructorA. Person(n,a);B. this(Person(n,a);C. this(n,a);D. this(name,age).-5精选文库23、 Which of the following statements about variables and their scopes are

19、true A. Instance variables are member variables of a class.B. Instance variables are declared with the static keyword.C. Local variables defined inside a method are created when the method is executed.D. Local variables must be initialized before they are used.24、 public void test() try oneMethod();

20、Which will display if oneMethod run normallyA. condition 1B. condition 2C. condition 3D. finally25、 Given the following code:public class Test void printValue(int m)while( -m > 10 )public static void main(String arg) int i=10;Test t= new Test();t.printValue(i);Which will be outputA. The value is

21、8B. The value is 9C. The value is 10D. The value is 11-6精选文库26、 Which of the following statements about declaration are trueA. Declaration of primitive types such as boolean, byte and so on does not allocate memory space for the variable.B. Declaration of primitive types such as boolean, byte and so

22、 on allocates memory space for the variable.C. Declaration of nonprimitive types such as String, Vector and so on does not allocate memory space for the object.D. Declaration of nonprimitive types such as String, Vector ans so on allocates memory space for the object.27、 In the Java API documentatio

23、n which sections are included in a class documentA. The description of the class and its purposeB. A list of methods in its super classC. A list of member variableD. The class hierarchy28、 Given the following code:1) public void modify() 2) int i, j, k;3) i = 100;4) while ( i > 0 ) 5) j = i * 2;6

24、)7) k = k + 1;8) i-;9) 10 Which line might cause an error during compilationA. line 4B. line 6C. line 7D. line 829、 Which of the following statements about variables and scope are trueA. Local variables defined inside a method are destroyed when the method is exited.B. Local variables are also calle

25、d automatic variables.C. Variables defined outside a method are created when the object is constructed.D. A method parameter variable continues to exist for as long as the object is needed in which the method is defined.-7精选文库30、A class design requires that a member variable cannot be accessible dir

26、ectly outside the class. Which modifier should be used to obtain the access controlA. publicB. no modifierC. protectedD. private31、 Given the following code fragment:1) String str = null;2)5)7 8)Which line will cause errorA. line 1B. line 2C. line 5D. line 832、 Which statements about Java code secur

27、ity are trueA. The bytecode verifier loads all classes needed for the execution of a program.B. Executing code is performed by the runtime interpreter.C. At runtime the bytecodes are loaded, checked and run in an interpreter.D. The class loader adds security by separating the namespaces for the clas

28、ses of the local file system from those imported from network sources.33、 Given the following code:public class Personint arr = new int10;public static void main(String a) Which statement is correctA. When compilation some error will occur.B. It is correct when compilation but will cause error when

29、running.C. The output is zero.D. The output is null.34、 public class Parent -8精选文库public int addValue( int a, int b) int s;s = a+b;return s;class Child extends Parent Which methods can be added into class ChildA. int addValue( int a, int b )/ do something.B. public void addValue ()/ do something.C.

30、public int addValue( int a )/ do something.D. public int addValue( int a, int b )throws MyException /do something.35、 Which statements about thread are trueA. Once a thread is created, it can star running immediately.B. To use the start() method makes a thread runnable, but it does not necessarily s

31、tart immediately.C. When a thread stops running because of pre-emptive, it is placed at the front end of the runnable queue.D. A thread may cease to be ready for a variety of reasons.36、A member variable defined in a class can be accessed only by the classes in the same package. Which modifier shoul

32、d be used to obtain the access controlA. privateB. no modifierC. publicD. protected37、 A public member vairable called MAX_LENGTH which is int type, the value of the variable remains constant value 100. Use a short statement to define the variable.A. public int MAX_LENGTH=100;B. final int MAX_LENGTH

33、=100;C. final public int MAX_LENGTH=100;D. public final int MAX_LENGTH=100.38、 Which expressions are correct to declare an array of 10 String objectsA. char str;B. char str;C. String str;D. String str10;39、 Which fragments are correct in Java source fileA. package testpackage;-9精选文库public class Test

34、/do something.package testpackage;public class Test/ do something.class Person/ do something.public class Test/ do something.public class Test/ do something.40：String s= "hello"String t = "hello"char c = 'h','e','l','l','o' ;Which return tr

35、ueA. s.equals(t);B. t.equals(c);C. s=t;D. t.equals(new String("hello");E. t=c.41. Which of the following statements are legalA. long l = 4990;B. int i = 4L;C. float f = 1.1;D. double d = 34.4;E. double t = 0.9F.42、public class Parent int change() class Child extends Parent Which methods ca

36、n be added into class ChildA. public int change()B. int chang(int i)C. private int change()D. abstract int chang()-10精选文库43、 class Parent String one, two;public Parent(String a, String b)one = a;two = b;public class Child extends Parent public Child(String a, String b)super(a,b);public void print()p

37、ublic static void main(String arg)Parent p = new Parent("south", "north");Parent t = new Child("east", "west");p.print();t.print();Which of the following is correctA. Cause error during compilation.B. south eastC. south to north east to westD. south to north e

38、astE. southeast to west44、 Given the uncompleted method:1)2) success = connect() 3 if (success=-1) 4 throw new TimedOutException(); 5 6TimedOutException is not a RuntimeException. Which can complete the method ofdeclaration when added at line 1-11精选文库A. public void method()B. public void method() th

39、rows ExceptionC. public void method() throws TimedOutExceptionD. public void method() throw TimedOutExceptionE. public throw TimedOutException void method()45、 Given the following code:1) class Parent 2 private String name;3 public Parent()4 5) public class Child extends Parent 6 private String depa

40、rtment;7 public Child() 8 public String getValue() return name; 9) public static void main(String arg) 10 Parent p = new Parent();11 12) Which line will cause errorA. line 3B. line 6C. line 7D. line 8E. line 1046、 The variable "result" is boolean. Which expressions are legal A. result = tr

41、ue;B. if ( result ) / do something. C. if ( result!= 0 ) / so something. D. result = 147、 Class Teacher and Student are subclass of class Person.Person p;Teacher t;Student s;p, t and s are all non-null.if(t instanceof Person) s = (Student)t; What is the result of this sentenceA. It will construct a

42、Student object.B. The expression is legal.C. It is illegal at compilation.D. It is legal at compilation but possible illegal at runtime.-12精选文库48、 Given the following class:public class Samplelong length;public Sample(long l) length = l; public static void main(String arg)Sample s1, s2, s3;s1 = new

43、Sample(21L);s2 = new Sample(21L);s3 = s2;long m = 21L;Which expression returns trueA. s1 = s2;B. s2 = s3;C. m = s1;D. s1.equals(m).49、 Which classes can be used as the argument of the constructor of the class FilterInputStreamA. FilterOutputStreamB. FileC. InputStreamD. RandomAccessFile50、 Which cla

44、sses can be used as the argument of the constructor of the class FileInputStreamA. InputStreamB. FileC. FileOutputStreamD. String51、 Which is not a method of the class InputStreamA. int read(byte)B. void flush()C. void close()D. int available()52、 Given the following code:class Person String name,de

45、partment;public void printValue()-13精选文库public class Teacher extends Person int salary;public void printValue()/ doing the same as in the parent method printValue()/Which expression can be added at the "doing the same as." part of the method printValue()A. printValue();B. this.printValue()

46、;C. person.printValue();D. super.printValue().53. Which of the following assignment is not correctA. float f = 11.1;B. double d = 5.3E12;C. double d = 3.14159;D. double d = 3.14D.Linux基础1. Linux 文件权限一共10 位长度，分成四段，第三段表示的内容是_。A 文件类型B 文件所有者的权限C 文件所有者所在组的权限D 其他用户的权限2在使用mkdir 命令创建新的目录时，在其父目录不存在时先创建父目录的选项

47、是_。A -m B -d C -f D p3. 具有很多 C 语言的功能，又称过滤器的是_ 。A cshB tcshC awkD sed4. 下列文件中，包含了主机名到IP 地址的映射关系的文件是：_ 。A /etc/HOSTNAME B /etc/hosts C /etc/resolv.conf D /etc/networks5. 命令可以从文本文件的每一行中截取指定内容的数据。_A cp B dd C fmt D cut6对名为fido 的文件用chmod 551 fido进行了修改，则它的许可权是_ 。-14精选文库A -rwxr-xr-x B -rwxr-r- C -r-r-r- D

48、-r-xr-x x7 用 ls al 命令列出下面的文件列表，_ 文件是符号连接文件。A -rw-rw-rw- 2 hel-s users 56 Sep 09 11:05 helloB -rwxrwxrwx 2 hel-s users 56 Sep 09 11:05 goodbeyC drwxr-r- 1 hel users 1024 Sep 10 08:10 zhangD lrwxr-r- 1 hel users 2024 Sep 12 08:12 cheng8在 vi 编辑器中的命令模式下，键入_可在光标当前所在行下添加一新行。A <a> B <o> C <I> D A9在 vi 编辑器中的命令模式下，重复上一次对编辑的文本进行的操作，可使用_命令。A 上箭头 B 下箭头 C <.> D <*>10用命令 ls -al 显示出文件 ff 的描述如下所示，由此可知文件ff的类型为 _。-rwxr-xr- 1 root root 599 Cec 10 17:12 ffA 普通文件 B 硬链接 C 目录 D 符号链接11删除文件命令为： _ 。A mkdir B rmdir C mv D rm12对文件进行归档的命令为_ 。A dd B cpio C gzi