抽象类、接口和包作业

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1、抽象类、接口和包——作业Question1Given:11.publicinterfaceStatus{12./*insertcodehere*/intMY_VALUE=10;13.}Whichthreearevalidonline12?(Choosethree.)A.finalB.staticC.nativeD.publicE.privateF.abstractG.protectedQuestion2Given:10.interfaceFoo{}11.classAlphaimplementsFoo{}12.classBetaextendsAlpha{}13.classDelt

2、aextendsBeta{14.publicstaticvoidmain(String[]args){15.Betax=newBeta();16.//insertcodehere17.}18.}Whichcode,insertedatline16,willcauseajava.lang.ClassCastException?A.Alphaa=x;B.Foof=(Delta)x;C.Foof=(Alpha)x;D.Betab=(Beta)(Alpha)x;Question3Given:10.packagecom.sun.scjp;11.publicclassGeodetics{1

3、2.publicstaticfinaldoubleDIAMETER=12756.32;//kilometers13.}WhichtwocorrectlyaccesstheDIAMETERmemberoftheGeodeticsclass?(Choosetwo.)A.importcom.sun.scjp.Geodetics;publicclassTerraCarta{publicdoublehalfway(){returnGeodetics.DIAMETER/2.0;}}B.importstaticcom.sun.scjp.Geodetics;publicclassTerraCa

4、rta{publicdoublehalfway(){returnDIAMETER/2.0;}}C.importstaticcom.sun.scjp.Geodetics.*;publicclassTerraCarta{publicdoublehalfway(){returnDIAMETER/2.0;}}D.packagecom.sun.scjp;publicclassTerraCarta{publicdoublehalfway(){returnDIAMETER/2.0;}}Question4Given:10.interfaceFoo{intbar();}11.publicclas

5、sSprite{12.publicintfubar(Foofoo){returnfoo.bar();}13.publicvoidtestFoo(){14.fubar(15.//insertcodehere16.);17.}18.}Whichcode,insertedatline15,allowstheclassSpritetocompile?A.Foo{publicintbar(){return1;}}B.newFoo{publicintbar(){return1;}}C.newFoo(){publicintbar(){return1;}}D.newclassFoo{publi

6、cintbar(){return1;}}Question5Given:1.publicinterfaceA{2.StringDEFAULT_GREETING=“HelloWorld”;3.publicvoidmethod1();4.}AprogrammerwantstocreateaninterfacecalledBthathasAasitsparent.Whichinterfacedeclarationiscorrect?A.publicinterfaceBextendsA{}B.publicinterfaceBimplementsA{}C.publicinterfaceBi

7、nstanceOfA{}D.publicinterfaceBinheritsFromA{}Question6Given:1.interfaceTestA{StringtoString();}2.publicclassTest{3.publicstaticvoidmain(String[]args){4.System.out.println(newTestA(){5.publicStringtoString(){return“test”;}6.});7.}8.}Whatistheresult?