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1、1. Given:Integeri=newInteger(42);Longl=newLong(42);Doubled=newDouble(42.0);WhichtwoexpressionsevaluatetoTrue?A. (i=1)B. (i=d)C. (d=1)D. (i.equals(l)E. (d.equals(l)F. (i.equals(42)G. noneofaboveAnswer:2. Given:publicclassFoopublicstaticvoidmain(Stringargs)StringBuffera=newStringBuffer(A);StringBuffer
2、b=newStringBuffer(B);operate(a,b);System.out.println(a+,+b);staticvoidoperate(StringBufferx,StringBuffery)x.append(y);y=x;Whatistheresult?A. Thecodecompilesandprints“A,B”.B. Thecodecompilesandprints“A,A”.C. Thecodecompilesandprints“B,B”.D. Thecodecompilesandprints“AB,B”.E. Thecodecompilesandprints“A
3、B,AB”.F. Thecodedoesnotcompilebecause“+”cannotbeoverloadedforStringBuffer.Answer:3. Given:classBaseClassprivatefloatx=1.0f;protectedfloatgetVar()returnx;classSubclassextendsBaseClassprivatefloatx=2.0f;/inserthereWhichtwoarevalidexamplesofmethodoverriding?A. floatgetVar()returnx;B. publicfloatgetVar(
4、)returnx;C. publicdoublegetVar()returnx;D. protectedfloatgetVar()returnx;E. publicfloatgetVar(floatf)returnf;Answer:4. WhichofthefollowingaremethodsoftheRunnableinterfaceA) runB) startC) yieldD) stopAnswer:5. Whichofthefollowingarelegalstatements?A) floatf=1/3;B) inti=1/3;C) floatf=1.01;D) doubled=9
5、99d;Answer:6. Given:publicclasstest(publicstaticvoidmain(stringargs)Stringfoo=args1;Stringbaz=args2;Stringbax=args3;Andthecommandlineinvocation:JavaTestredgreenblueWhatistheresult?A. bazhasthevalueof“”B. bazhasthevalueofnullC. bazhasthevalueof“red”D. bazhasthevalueof“blue”E. baxhasthevalueof“green”F
6、. thecodedoesnotcompileG. theprogramthrowsanexceptionAnswer:7. Whichofthefollowingstatementsaretrue?A) ThegarbagecollectionalgorithminJavaisvendorimplementedB) ThesizeofprimitivesisplatformdependentC) Thedefaulttypeforanumericalliteralwithdecimalcomponentisafloat.D) YoucanmodifythevalueinanInstanceo
7、ftheIntegerclasswiththesetValuemethodAnswer:8. Given:inti=1,j=10;doif(i+-j)continue;while(i5);Afterexecution,whatarethevaluesforiandj?A. i=6andj=5B. i=5andj=5C. i=6andj=4D. i=5andj=6E. i=6andj=6Answer:9. Given:importjava.io.IOException;publicclassExceptionTestpublicstaticvoidmain(Stringargs)trymetho
8、dA();catch(IOExceptione)System.out.println(CaughtIOException);catch(Exceptione)System.out.println(CaughtException);publicvoidmethodA()thrownewIOException();Whatistheresult?A. Thecodewillnotcompile.B. Theoutputis:caughtexception.C. Theoutputis:caughtIOException.D. Theprogramexecutesnormallywithoutpri
9、ntingamessage.Answer:10. Given:publicclassTestpublicstaticStringoutput=;publicstaticvoidfoo(inti)tryif(i=1)thrownewException();output+=1;catch(Exceptione)output+=2;return;finallyoutput+=3;output+=4;publicstaticvoidmain(Stringargs)foo(0);foo(1);/line24Whatisthevalueofthevariableoutputatline24?Answer:
10、11. Given:publicclassFooimplementsRunnable/line1publicvoidrun(Threadt)/line2System.out.println(Running.);publicstaticvoidmain(Stringargs)newThread(newFoo().start();Whatistheresult?A. AnexceptionisthrownB. TheprogramexistswithoutprintinganythingC. Anerroratline1causescompilationtofail.D. Anerroratlin
11、e2causesthecompilationtofail.E. “Running”isprintedandtheprogramexitsAnswer:12. Given:ClassOne.javapackagecom.abc.pkg1;publicclassClassOneprivatecharvar=a;chargetVar()returnvar;ClassTest.javapackagecom.abc.pkg2;importcom.abc.pkg1.ClassOne;publicclassClassTestextendsClassOnepublicstaticvoidmain(String
12、args)chara=newClassOne().getVar();/line5charb=newClassTest().getVar();/line6Whatistheresult?A. Compilationwillfail.B. Compilationsucceedsandnoexceptionsarethrown.C. Compilationsucceedsbutanexceptionisthrownatline5inClassTest.java.D. Compilationsucceedsbutanexceptionisthrownatline6inClassTest.java.An
13、swer:13. Whichisavalididentifier?A. falseB. defaultC. _objectD. a-classAnswer:14Ifyourunthecodebelow,whatgetsprintedout?Strings=newString(Bicycle);intiBegin=1;chariEnd=3;System.out.println(s.substring(iBegin,iEnd);A) BicB) icC) icyD) error:nomethodmatchingsubstring(int,char)Answer:15Whatwillhappenwh
14、enyouattempttocompileandrunthefollowingcodepublicclassMySwitchpublicstaticvoidmain(Stringargv)MySwitchms=newMySwitch();ms.amethod();publicvoidamethod()intk=10;switch(k)default:/Putthedefaultatthebottom,nothereSystem.out.println(Thisisthedefaultoutput);break;case10:System.out.println(ten);case20:System.out.println(twenty);break;A) NoneoftheseoptionsB) CompiletimeerrortargetofswitchmustbeanintegraltypeC) CompileandrunwithoutputThisisthedefaultoutputD) CompileandrunwithoutputofthesinglelinetenAnswer:第二部分：J2EE部份1简述J2EEArchitecture。2.简述JSP在WebContainer中的生命周期。3如何使用数据库连接池？有什么好处
