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选择题 1:Which of the following statements are not legal? A.long l = 4990; B.int i = 4L; C.double d = 34.4; D.double t = 0.9F. 2: 1. Whatwillbetheresultofexecutingthefollowingcode? 2. 3. publicstaticvoidmain(Stringargs) 4. 5. chardigit=a; 6. for(inti=0;i10;i+) 7. 8. switch(digit) 9. 10. casex: 11. 12. intj=0; 13. System.out.println(j); 14. 15. default: 16. 17. intj=100; 18. System.out.println(j); 19. 20. 21. 22. inti=j; 23. System.out.println(i); 24. 25. 26. Choices:What will be the result of executing the following code? public static void main(String args) char digit = a; for (int i = 0; i ” 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 12:使用 JDBC 可以做到的是 A.把二进制代码传送到任何关系数据库中 B.把 Java 源代码传送到任何关系数据库中 C.把表单信息传送到任何关系数据库中 D.很容易地把 SQL 语句传送到任何关系数据库中 13: Which of the following statements are true? A.The automatic garbage collection of the JVM prevents programs from ever running out of memory B.A program can suggest that garbage collection be performed and force it C.Garbage collection is platform independent D.An object becomes eligible for garbage collection when all references denoting it are set to null. 14: 1. Whathappenswhenyoutrytocompileandrunthefollowingprogram? 2. classMystery 3. Strings; 4. publicstaticvoidmain(Stringargs) 5. Mysterym=newMystery(); 6. m.go(); 7. 8. voidMystery() 9. s=”constructor”; 10. 11. voidgo() 12. System.out.println(s); 13. 14. What happens when you try to compile and run the following program?class MysteryString s;public static void main(String args)Mystery m=new Mystery();m.go();void Mystery()s=”constructor”;void go()System.out.println(s);A.this code compliles but throws an exception at runtime B.this code runs but nothing appears in the standard output C.this code runs and “constructor” in the standard output D.this code runs and writes ”null” in the standard output 15: 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) 16: 1. Whichisthemostappropriatecodesnippetthatcanbeinsertedatline18inthefollowingcode? 2. 3. (Assumethatthecodeiscompiledandrunwithassertionsenabled) 4. 5. 1.importjava.util.*; 6. 7. 2. 8. 9. 3.publicclassAssertTest 10. 11. 4. 12. 13. 5.privateHashMapcctld; 14. 15. 6. 16. 17. 7.publicAssertTest() 18. 19. 8. 20. 21. 9.cctld=newHashMap(); 22. 23. 10.cctld.put(in,India); 24. 25. 11.cctld.put(uk,UnitedKingdom); 26. 27. 12.cctld.put(au,Australia); 28. 29. 13./morecode. 30. 31. 14. 32. 33. 15./othermethods. 34. 35. 16.publicStringgetCountry(StringcountryCode) 36. 37. 17. 38. 39. 18./Whatshouldbeinsertedhere? 40. 41. 19.Stringcountry=(String)cctld.get(countryCode); 42. 43. 20.returncountry; 44. 45. 21. 46. 47. 22.Which is the most appropriate code snippet that can be inserted at line 18 in the following code?(Assume that the code is compiled and run with assertions enabled)1. import java.util.*;2. 3. public class AssertTest4. 5. private HashMap cctld;6. 7. public AssertTest()8. 9. cctld = new HashMap();10. cctld.put(in, India);11. cctld.put(uk, United Kingdom);12. cctld.put(au, Australia);13. / more code. 14. 15. / other methods . 16. public String getCountry(String countryCode)17. 18. / What should be inserted here?19. String country = (String)cctld.get(countryCode);20. return country;21. 22. A.assert countryCode != null; B.assert countryCode != null : Country code can not be null ; C.assert cctld != null : No country code data is available; D.assert cctld : No country code data is available; 简答题 17:jsp有哪些内置对象?作用分别是什么? 18:写出不