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选择题 1: 1. Givethefollowingmethod: 2. publicvoidmethod() 3. Stringa,b; 4. a=newString(“helloworld”); 5. b=newString(“gameover”); 6. System.out.println(a+b+”ok”); 7. a=null; 8. a=b; 9. System.out.println(a); 10. 11. Intheabsenceofcompileroptimization,whichistheearliestpointtheobjectareferedisdefinitelyelibiletobegarbagecollection.Give the following method: public void method( ) String a,b; a=new String(“hello world”); b=new String(“game over”); System.out.println(a+b+”ok”); a=null; a=b; System.out.println(a); In the absence of compiler optimization, which is the earliest point the object a refered is definitely elibile to be garbage collection.A.before line 5 B.before line 6 C.before line 7 D.before line 9 2:在软件生命周期中，下列哪个说法是不准确的? A.软件生命周期分为计划、开发和运行三个阶段 B.在计划阶段要进行问题焉醛和需求分析 C.在开发后期要进行编写代码和软件测试 D.在运行阶段主要是进行软件维护 3:Which of the following answer is correct to express the value 8 in octal number? A.010 B.0x10 C.08 D.0x8 4:Use the operator “” and “”. Which statement is true? A.1010 0000 0000 0000 0000 0000 0000 0000 4 give 0000 1010 0000 0000 0000 0000 0000 0000 B.1010 0000 0000 0000 0000 0000 0000 0000 4 give 1111 1010 0000 0000 0000 0000 0000 0000 C.1010 0000 0000 0000 0000 0000 0000 0000 4 give 0000 0000 0000 0000 0000 0000 0000 0000 D.1010 0000 0000 0000 0000 0000 0000 0000 4 give 1111 1010 0000 0000 0000 0000 0000 0000 5:Which statement about the garbage collection mechanism are true? A.Garbage collection require additional programe code in cases where multiple threads are running. B.The programmer can indicate that a reference through a local variable is no longer of interest. C.The programmer has a mechanism that explicity and immediately frees the memory used by Java objects. D.The garbage collection mechanism can free the memory used by Java Object at explection time. 6:鉴于Java的特点，它最适合的计算环境是 A.并行计算环境 B.分布式计算环境 C.高强度计算环境 D.开放式计算环境 7:在下述选项时,没有构成死循环的程序是 A.int i=100 while (1) i=i%100+1; if (i100) break; B.for (;); C.int k=1000; do +k; while(k=10000); D.int s=36; while (s);-s; 8: 1. Givethefollowingjavasourcefragement: 2. /pointx 3. publicclassInteresting 4. /dosomething 5. 6. WhichstatementiscorrectlyJavasyntaxatpointx?Give the following java source fragement:/point xpublic class Interesting/do somethingWhich statement is correctly Java syntax at point x? A.public class MyClass/do other thing B.static int PI=3.14 C.class MyClass/do something D.none 9: 1. Whatwillhappenwhenyouattempttocompileandrunthefollowingcode? 2. 3. classBase 4. 5. 6. 7. inti=99; 8. 9. publicvoidamethod() 10. 11. 12. 13. System.out.println(Base.amethod(); 14. 15. 16. 17. Base() 18. 19. 20. 21. amethod(); 22. 23. 24. 25. 26. 27. publicclassDerivedextendsBase 28. 29. 30. 31. inti=-1; 32. 33. 34. 35. publicstaticvoidmain(Stringargv) 36. 37. 38. 39. Baseb=newDerived(); 40. 41. System.out.println(b.i); 42. 43. b.amethod(); 44. 45. 46. 47. publicvoidamethod() 48. 49. 50. 51. System.out.println(Derived.amethod(); 52. 53. 54. 55. 56. 57. Choices:What will happen when you attempt to compile and run the following code? class Base int i = 99; public void amethod() System.out.println(Base.amethod(); Base() amethod(); public class Derived extends Baseint i = -1; public static void main(String argv) Base b = new Derived(); System.out.println(b.i); b.amethod(); public void amethod() System.out.println(Derived.amethod(); Choices:A.Derived.amethod() -1 Derived.amethod() B.Derived.amethod() 99 C.Compile time error D.Derived.amethod() 10: 1. publicclassOuterClass 2. privatedoubled1=1.0; 3. /insertcodehere 4. 5. Youneedtoinsertaninnerclassdeclarationatline3.Whichtwoinnerclassdeclarationsare 6. valid?public class OuterClass private double d1 = 1.0;/insert code hereYou need to insert an inner class declaration at line 3. Which two inner class declarations arevalid?A.class InnerOne public static double methoda() return d1; B.public class InnerOne static double methoda() return d1; C.private class InnerOne double methoda() return d1; D.static class InnerOne protected double methoda() return d1; 11: 1. Whatwillhappenwhenyouattempttocompileandrunthefollowingcode? 2. 3. publicclassStatic 4. 5. 6. 7. static8. 9. 10. 11. intx=5; 12. 13. 14. 15. staticintx,y; 16. 17. publicstaticvoidmain(Stringargs) 18. 19. 20. 21. x-; 22. 23. myMethod(); 24. 25. System.out.println(x+y+x); 26. 27. 28. 29. publicstaticvoidmyMethod() 30. 31. 32. 33. y=x+x; 34. 35. 36. 37. 38. 39. Choices:What will happen when you attempt to compile and run the following code? public class Staticstaticint x = 5; static int x,y;public static void main(String args) x-; myMethod(); System.out.println(x + y + +x); public static void myMethod()y = x+ + +x; Choices:A.prints : 2 B.prints : 3 C.prints : 7 D.prints : 8 12: 1. Givethecodefragment: 2. if(x4) 3. System.out.println(“Test1”); 4. elseif(x9) 5. System.out.println(“Test2”); 6. else 7. System.out.println(“Test3”); 8. Whichrangeofvaluexwouldproduceofoutput“Test2”?Give the code fragment:if(x4)System.out.println(“Test 1”);else if (x9)System.out.println(“Test 2”);else System.out.println(“Test 3”);Which range of value x would produce of output “Test 2”? A.x4 C.x9 D.None 13: 1. Inthefollowingcode,whichistheearlieststatement,wheretheobjectoriginallyheldine,maybegarbagecollected: 2. 1.publicclassTest 3. 4. 2.publicstaticvoidmain(Stringargs) 5. 6. 3.Employeee=newEmployee(Bob,48); 7. 8. 4.e.calculatePay(); 9. 10. 5.System.out.println(e.printDetails(); 11. 12. 6.e=null; 13. 14. 7.e=newEmployee(Denise,36); 15. 16. 8.e.calculatePay(); 17. 18. 9.System.out.println(e.printDetails(); 19. 20. 10. 21. 22. 11. 23. OnlyOne:In the following code, which is the earliest statement, where the object originally held in e, may be garbage collected: 1.public class Test 2. public static void main (String args ) 3. Employee e = new Employee(Bob, 48); 4. e.calculatePay(); 5. System.out.println(e.printDetails(); 6. e = null; 7. e = new Employee(Denise, 36); 8. e.calculatePay(); 9. System.out.println(e.printDetails(); 10. 11.Only One: A.Line 10 B.Line 11 C.Line 7 D.Line 8 14:关于垃圾收集的哪些叙述是对的。 A.程序开发者必须自己创建一个线程进行内存释放的工作。 B.垃圾收集将检查并释放不再使用的内存。 C.垃圾收集允许程序开发者明确指定并立即释放该内存。 D.垃圾收集能够在期望的时间释放被java对象使用的内存。 15:Math.round(-11.5)等於多少? A.-11 B.-12 C.-11.5 D.none 16: 1. Whatresultsfromattemptingtocompileandrunthefollowingcode? 2. 3. publicclassTernary 4. 5. 6. 7. publicstaticvoidm