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选择题 1:Which statement about listener is true? A.Most component allow multiple listeners to be added. B.If multiple listener be add to a single component, the event only affected one listener. C.Component don?t allow multiple listeners to be add. D.none 2:以下的C程序代码片段运行后C和d的值分别是多少 Int a =1,b =2; Int c,d; c =(a&b)&a; d =(a&b)&a; A.0,0 B.0,1 C.1,0 D.1,1 3: 1. 1.publicclassX 2. 2.publicobjectm() 3. 3.objecto=newfloat(3.14F); 4. 4.objectoa=newobject1; 5. 5.oa0=o; 6. 6.o=null; 7. 7.oa0=null; 8. 8.returno; 9. 9. 10. 10. 11. Whenisthefloatobjectcreatedinline3,eligibleforgarbagecollection? 1. public class X 2. public object m () 3. object o = new float (3.14F); 4. object oa = new object 1; 5. oa0= o; 6. o = null; 7. oa0 = null; 8.return o; 9. 10. When is the float object created in line 3, eligible for garbage collection? A.Just after line 5 B.Just after line 6 C.Just after line 7 D.Just after line 8(that is, as the method returns) 4:Which is the main() method return of a application? A.String B.byte C.char D.void 5: 1. Strings=”ExampleString”;Whichoperationisnotlegal?String s=”Example String”;Which operation is not legal?A.int i=s.length(); B.s3=”x”; C.String short_s=s.trim(); D.String t=”root”+s; 6:软件生命周期的瀑布模型把软件项目分为3个阶段、8个子阶段，以下哪一个是正常的开发顺序? A.计划阶段、开发阶段、运行阶段 B.设计阶段、开发阶段、编码阶段 C.设计阶段、编码阶段、维护阶段 D.计划阶段、编码阶段、测试阶段 7: 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() 8: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. 9: 1. 给出下面的代码片断。下面的哪些陈述为错误的? 2. 1)publicvoidcreate() 3. 2)VectormyVect; 4. 3)myVect=newVector(); 5. 4)给出下面的代码片断。下面的哪些陈述为错误的?1) public void create() 2) Vector myVect;3) myVect = new Vector();4) A.第二行的声明不会为变量myVect分配内存空间。 B.第二行语句创建一个Vector类对象。 C.第三行语句创建一个Vector类对象。 D.第三行语句为一个Vector类对象分配内存空间 10: Consider the class hierarchy shown below: - class FourWheeler implements DrivingUtilities class Car extends FourWheeler class Truck extends FourWheeler class Bus extends FourWheeler class Crane extends FourWheeler - Consider the following code below: 1.DrivingUtilities du; 2.FourWheeler fw; 3.Truck myTruck = new Truck(); 4.du = (DrivingUtilities)myTruck; 5.fw = new Crane(); 6.fw = du; Which of the statements below are true? Choices: A.Line 4 will not compile because an interface cannot refer to an object. B.The code will compile and run. C.The code will not compile without an explicit cast at line 6, because going down the hierarchy without casting is not allowed. D.The code will compile if we put an explicit cast at line 6 but will throw an exception at runtime. 11: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 12: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; 13:Which declares for native method in a java class corrected? A.public native void method() B.public native void method(); C.public native method(); D.public void native method(); 14: 1. Whatwillbetheresultofexecutingthefollowingcode? 2. booleana=true; 3. booleanb=false; 4. booleanc=true; 5. if(a=true) 6. if(b=true) 7. if(c=true)System.out.println(Somethingsaretrueinthisworld); 8. elseSystem.out.println(Nothingistrueinthisworld!); 9. elseif(a&(b=c)System.out.println(Itstooconfusingtotellwhatistrueandwhatisfalse); 10. elseSystem.out.println(Heythiswontcompile); 11. 12. Choices:What will be the result of executing the following code? boolean a = true; boolean b = false; boolean c = true; if (a = true) if (b = true) if (c = true) System.out.println(Some things are true in this world); else System.out.println(Nothing is true in this world!); else if (a & (b = c) System.out.println(Its too confusing to tell what is true and what is false); else System.out.println(Hey this wont compile); Choices:A.The code wont compile B.Some things are true in this world will be printed C.Hey this wont compile will be printed D.None of these 15: 1. 下述程序代码中有语法错误的行是（）。 2. inti,ia10,ib10;/*第一行*/3. for(i=0;i=9;i+)/*第2行*/4. iai=0;/*第3行*/5. ib=ia;/*第4行*/下述程序代码中有语法错误的行是（ ）。int i,ia10,ib10; /*第一行*/for (i=0;i=9;i+) /*第2行*/ iai=0; /*第3行*/ib=ia; /*第4行*/A.第1行 B.第2行 C.第3行 D.第4行 16: 1. Whatresultsfromattemptingtocompileandrunthefollowingcode? 2. 3. publicclassTernary 4. 5. 6. 7. publicstaticvoidmain(Stringargs) 8. 9. 10. 11. inta=5; 12. 13. System.out.println(Valueis-+(a5)?9.9:9); 14. 15. 16. 17. 18. 19. Choices:What results from attempting to compile and run the following code? public class Ternarypublic static void main(