文思创新笔试题.doc

文思创新软件技术有限公司杭州分公司 java开发工程师（工作地杭州-急聘）笔试题 公司简介 所在省市:-深圳 公司地址:中国杭州市滨江区东信大道66号东方通信城 E 座 A325 室 查看地图 电子邮箱: zhaopin_ 公司性质:计算机软件计算机软件公司 返回上级目录 选择题 1: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; 2:Which method you define as the starting point of new thread in a class from which new the thread can be excution? A.public void start() B.public void run() C.public void runnable() D.public static void main(String args) 3: Whatwillbetheresultofexecutingthefollowingcode? /Filename;SuperclassX.java packagepackageX; publicclassSuperclassX protectedvoidsuperclassMethodX() intsuperclassVarX; /FilenameSubclassY.java 1.packagepackageX.packageY; 2. 3.publicclassSubclassYextendsSuperclassX 4. 5.SuperclassXobjX=newSubclassY(); 6.SubclassYobjY=newSubclassY(); 7.voidsubclassMethodY() 8. 9.objY.superclassMethodX(); 10.inti; 11.i=objY.superclassVarX; 12. 13. Choices:What will be the result of executing the following code? / Filename; SuperclassX.javapackage packageX; public class SuperclassXprotected void superclassMethodX()int superclassVarX; / Filename SubclassY.java1.package packageX.packageY;2.3.public class SubclassY extends SuperclassX4.5.SuperclassX objX = new SubclassY();6.SubclassY objY = new SubclassY();7.void subclassMethodY()8.9.objY.superclassMethodX();10.int i;11.i = objY.superclassVarX;12.13. Choices:A.Compilation error at line 5 B.Compilation error at line 9 C.Runtime exception at line 11 D.None of these 4: publicclassOuterClass privatedoubled1=1.0; /insertcodehere Youneedtoinsertaninnerclassdeclarationatline3.Whichtwoinnerclassdeclarationsare 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; 5: Givethefollowingjavaclass: publicclassExample publicstaticvoidmain(Stringargs) staticintx=newint15; System.out.println(x5); Whichstatementiscorrected?Give the following java class:public class Examplepublic static void main(String args)static int x = new int15;System.out.println(x5);Which statement is corrected?A.When compile, some error will occur. B.When run, some error will occur. C.Output is zero. D.Output is null. 6: Whatwillhappenwhenyouattempttocompileandrunthefollowingcode? (Assumethatthecodeiscompiledandrunwithassertionsenabled.) publicclassAssertTest publicvoidmethodA(inti) asserti=0:methodB(); System.out.println(i); publicvoidmethodB() System.out.println(Thevaluemustnotbenegative); publicstaticvoidmain(Stringargs) AssertTesttest=newAssertTest(); test.methodA(-10); What will happen when you attempt to compile and run the following code?(Assume that the code is compiled and run with assertions enabled.)public class AssertTestpublic void methodA(int i)assert i = 0 : methodB();System.out.println(i);public void methodB() System.out.println(The value must not be negative);public static void main(String args)AssertTest test = new AssertTest();test.methodA(-10); A.it will print -10 B.it will result in AssertionError showing the message-“the value must not be negative”. C.the code will not compile. D.None of these. 7:Which fragments are not correct in Java source file? A.package testpackage; public class Test/do something. B.import java.io.*; package testpackage; public class Test/ do something. C.import java.io.*; class Person/ do something. public class Test/ do something. D.import java.io.*; import java.awt.*; public class Test/ do something. 8: Givethefollowingjavasourcefragement: /pointx publicclassInteresting /dosomething 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: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(); 10: 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; 11:What is written to the standard output given the following statement:System.out.println(4|7); Select the right answer: A.4 B.5 C.6 D.7 12: 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: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() 13: Whatistheresultwhenyoucompileandrunthefollowingcode? publicclassThrowsDemo staticvoidthrowMethod() System.out.println(InsidethrowMethod.); thrownewIllegalAccessException(demo); publicstaticvoidmain(Stringargs) try throwMethod(); catch(IllegalAccessExceptione) System.out.println(Caught+e); Choices:What is the result when you compile and run the following code? public class ThrowsDemo static void throwMethod() System.out.println(Inside throwMethod.); throw new IllegalAccessException(demo); public static void main(String args) try throwMethod(); catch (IllegalAccessException e) System.out.println(Caught + e); Choices:A.Compilation error B.Runtime error C.Compile successfully, nothing is printed. D.Inside throwMethod. followed by caught:java.lang.IllegalAccessExcption: demo 14: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 15: 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: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 16: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. 17: Whichisthemostappropriatecodesnippetthatcanbeinsertedatline18inthefollowingcode? (Assumethatthecodeiscompiledandrunwithassertionsenabled) 1.importjava.util.*; 2. 3.publicclassAssertTest 4. 5.privateHashMapcctld; 6. 7.publicAssertTest() 8. 9.cctld=newHashMap(); 10.cctld.put(in,India); 11.cctld.put(uk,UnitedKingdom); 12.cctld.put(au,Australia); 13./morecode. 14. 15./othermethods. 16.publicStringgetCountry(StringcountryCode) 17. 18./Whatshouldbeinsertedhere? 19.Stringcountry=(String)cctld.get(countryCode); 20.returncountry; 21. 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; 18: 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. 19: Which of the following statements are true? A.The automatic garbage collection of the JVM prevents programs from ever running out of memory B