java选择题题库

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1、窗体顶端2.WhichofthefollowingisavalidcharacterliteralinJava?(a)';'(b)'<='(c)"'"(d)"a"Correctanswer:A窗体底端2.AJavaidentifiermaybeginwithallbutwhichofthefollowing?(a)$(b)if(c)_(theunderscore)(d)0Correctansweris(d)3.InthecontextofJavaprogramming,garbagecollectionrefersto(a)automaticbalancingofp

2、arenthesisperformedbysomeeditors(b)removalofJavaprogramsthatcouldcausedamagetoasystem(c)conversionofcommentsintoJavadoccomments(d)automaticreturnofmemorytotheheapforobjectsnolongerrequiredbytheprogramCorrectansweris(d)9.WhatisthenameoftheJDKprogramthatprocessesJavadoccomments?(a)java(b

3、)javac(c)javacom(d)javadocCorrectansweris(d)2.Theprimitivefloating-pointtypesavailableinJavaare_____and_____.(a)real,double(b)float,double(c)real,float(d)single,realCorrectansweris(b)3.HowmanybytesarerequiredtorepresentaUnicodecharacter?(a)Four(b)One(c)Three(d)TwoCorrectansweris(d)5.Ho

4、wmanylinesofoutputwillbeproducedbythefollowingcodefragment?for(inti=0;i<4;++i){for(intj=1;j<3;++j){stdOut.println(i+j);(a)12(b)6(c)10(d)8Correctansweris(d)6.Howmanylinesofoutputwillbeproducedbythefollowingcodefragment?for(inti=0;i<3;++i){for(intj=0;j

5、)4(c)3(d)5Correctansweris(c)7.WhichofthefollowingstatementsaboutclassvariablesinJavaisnottrue?(a)Classvariablesrequirethemodifierstaticinthedeclarations.(b)Allobjectshavetheirowncopyoftheclassvariabledefinedintheinstantiatedclass.(c)Non-staticmethodsinaclasscanaccesstheclassvariabledef

6、inedinthesameclass.(d)Classvariablesdonotneedthereferencetotheobjectoftheinstantiatedclasstoaccessthem.Correctansweris(b)8.Thetermclassvariableisasynonymfor(a)aninstancevariable(b)aread-onlyvariable(c)aprivatedatafield(d)astaticdatafieldCorrectansweris(d)9.Whichofthefollowingpatternsof

7、charactersopensaJavadoccommentblock?(a)/**(b)//(c)/*(d)**/Correctansweris(a)2.Thetermwrapperclassesrefersto(a)theJavaclassesthatcontainatleasttwodatafields(b)theJavaclassesthatcontainthemselves(c)acollectionofJavaclassesthat"wrap"Javaprimitivetypes(d)acollectionofJavaclassesthatconta