选择题1:1.Give the following method: 2. public void method( ){ 3. String a,b; 4. a=new String(“hello world”); 5. b=new String(“game over”); 6. System.out.println(a+b+”ok”); 7. a=null; 8. a=b; 9. System.out.println(a); 10. } 11.In the absence of compiler optimization, which is the earliest point the object a refered is definitely elibile to be garbage collection. Givethefollowingmethod:publicvoidmethod(){Stringa,b;a=newString(“helloworld”);b=newString(“gameover”);System.out.println(a+b+”ok”);a=null;a=b;System.out.println(a);}Intheabsenceofcompileroptimization,whichistheearliestpointtheobjectareferedisdefinitelyelibiletobegarbagecollection.A.beforeline5B.beforeline6C.beforeline7D.beforeline92: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:Whichofthefollowingansweriscorrecttoexpressthevalue8inoctalnumber?A.010B.0x10C.08D.0x84:Usetheoperator“>>”and“>>>”.Whichstatementistrue? A.10100000000000000000000000000000>>4give00001010000000000000000000000000B.10100000000000000000000000000000>>4give11111010000000000000000000000000C.10100000000000000000000000000000>>>4give00000000000000000000000000000000D.10100000000000000000000000000000>>>4give111110100000000000000000000000005:Whichstatementaboutthegarbagecollectionmechanismaretrue?A.Garbagecollectionrequireadditionalprogramecodeincaseswheremultiplethreadsarerunning.B.Theprogrammercanindicatethatareferencethroughalocalvariableisnolongerofinterest.C.TheprogrammerhasamechanismthatexplicityandimmediatelyfreesthememoryusedbyJavaobjects.D.ThegarbagecollectionmechanismcanfreethememoryusedbyJavaObjectatexplectiontime.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.inti=100while(1){i=i%100+1;if(i>100)break;}B.for(;;);C.intk=1000;do{++k;}while(k>=10000);D.ints=36;while(s);--s;8: 1.Give the following java source fragement: 2.//point x 3.public class Interesting{ 4.//do something 5.} 6.Which statement is correctly Java syntax at point x? Givethefollowingjavasourcefragement://pointxpublicclassInteresting{//dosomething}WhichstatementiscorrectlyJavasyntaxatpointx?A.publicclassMyClass{//dootherthing…}B.staticintPI=3.14C.classMyClass{//dosomething…}D.none9:1.What will happen when you attempt to compile and run the following code? 2. 3.class Base 4. 5.{ 6. 7.int i = 99; 8. 9.public void amethod() 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.public class Derived extends Base 28. 1.{ 2. 3.int i = -1; 4. 5. 6. 7.public static void main(String argv[]) 8. 9.{ 10. 11. Base b = new Derived(); 12. 13. System.out.println(b.i); 14. 15. b.amethod(); 16. 17. } 18. 19. public void amethod() 20. 21.{ 22. 23. System.out.println("Derived.amethod()"); 24. 25. } 26. 27.} 28. 29.Choices: Whatwillhappenwhenyouattempttocompileandrunthefollowingcode?classBase{inti=99;publicvoidamethod(){System.out.println("Base.amethod()");}Base(){amethod();}}publicclassDerivedextendsBase{inti=-1;publicstaticvoidmain(Stringargv[]){Baseb=newDerived();System.out.println(b.i);b.amethod();}publicvoidamethod(){System.out.println("Derived.amethod()");}}Choices:A.Derived.amethod()-1Derived.amethod()B.Derived.amethod()99C.CompiletimeerrorD.Derived.amethod()10:1.public class OuterClass { 2.private double d1 = 1.0; 3.//insert code here 4.} 1.You need to insert an inner class declaration at line 3. Which two inner class declarations are 2.valid? publicclassOuterClass{privatedoubled1=1.0;//insertcodehere}Youneedtoinsertaninnerclassdeclarationatline3.Whichtwoinnerclassdeclarationsarevalid?A.classInnerOne{publicstaticdoublemethoda(){returnd1;}}B.publicclassInnerOne{staticdoublemethoda(){returnd1;}}C.privateclassInnerOne{doublemethoda(){returnd1;}}D.staticclassInnerOne{protecteddoublemethoda(){returnd1;}}11:1.What will happen when you attempt to compile and run the following code? 2. 3.public class Static 4. 5.{ 6. 7.static 8. 9.{ 10. 11.int x = 5; 12. 13.} 14. 15.static int x,y; 16. 17.public static void main(String args[]) 18. 19.{ 20. 21. x--; 22. 23. myMethod(); 24. 25. System.out.println(x + y + ++x); 26. 27.} 28. 29.public static void myMethod() 30. 31.{ 1. 2.y = x++ + ++x; 3. 4.} 5. 6.} 7. 8.Choices: Whatwillhappenwhenyouattempttocompileandrunthefollowingcode?publicclassStatic{static{intx=5;}staticintx,y;publicstaticvoidmain(Stringargs[]){x--;myMethod();System.out.println(x+y+++x);}publicstaticvoidmyMethod(){y=x+++++x;}}Choices:A.prints:2B.prints:3C.prints:7D.prints:812:1.Give the code fragment: 2.if(x>4){ 3.System.out.println(“Test 1”);} 4.else if (x>9){ 5.System.out.println(“Test 2”);} 6.else { 7.System.out.println(“Test 3”);} 8.Which range of value x would produce of output “Test 2”? Givethecodefragment:if(x>4){System.out.println(“Test1”);}elseif(x>9){System.out.println(“Test2”);}else{System.out.println(“Test3”);}Whichrangeofvaluexwouldproduceofoutput“Test2”?A.x<4B.x>4C.x>9D.None13:1.In the following code, which is the earliest statement, where the object originally held in e, may be garbage collected: 2. 1.public class Test { 3. 4. 2. public static void main (String args []) { 5. 6. 3. Employee e = new Employee("Bob", 48); 1. 2. 4. e.calculatePay(); 3. 4. 5. System.out.println(e.printDetails()); 5. 6. 6. e = null; 7. 8. 7. e = new Employee("Denise", 36); 9. 10. 8. e.calculatePay(); 11. 12. 9. System.out.println(e.printDetails()); 13. 14. 10. } 15. 16. 11.} 17.Only One: Inthefollowingcode,whichistheearlieststatement,wheretheobjectoriginallyheldine,maybegarbagecollected:1.publicclassTest{2.publicstaticvoidmain(Stringargs[]){3.Employeee=newEmployee("Bob",48);4.e.calculatePay();5.System.out.println(e.printDetails());6.e=null;7.e=newEmployee("Denise",36);8.e.calculatePay();9.System.out.println(e.printDetails());10.}11.}OnlyOne:A.Line10B.Line11C.Line7D.Line814: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.-11B.-12C.-11.5D.none 16:1.What results from attempting to compile and run the following code? 2. 3.public class Ternary 4. 5.{ 6. 7.public static void main(String args[]) 8. 9.{ 10. 11.int a = 5; 12. 13.System.out.println("Value is - " + ((a < 5) ? 9.9 : 9)); 14. 15.} 16. 17.} 18. 19.Choices: Whatresultsfromattemptingtocompileandrunthefollowingcode?publicclassTernary{publicstaticvoidmain(Stringargs[]){inta=5;System.out.println("Valueis-"+((a<5)?9.9:9));}}Choices:A.prints:Valueis-9B.CompilationerrorC.prints:Valueis-5D.Noneofthese简答题17:写一个方法，在JAVA,C/C++源代码中，检查花括弧（是“（”与“）”，“{”与“}”）是否匹配，若不匹配，则输出不匹配花括弧所在的行与列。18:abstractclass和interface有什么区别?19:spring中Bean的作用域有哪几种？20:Jdo是什么?21:比较两个字符串，用O(n)时间和恒量空间。22:两种不同的方法计算unsignedx有多少1bits，如x=3，为00000011，有2个123:在java中一个类被声明为final类型，表示了什么意思？24:如何给weblogic指定大小的内存?25:Error与Exception有什么区别？
