publicclassPet{privateStringname;publicPet(Stringname){this.name=name;}publicvoidspeak(){System.out.print(name);}}publicclassDogextendsPet{publicDog(Stringname){super(name);}publicvoidspeak(){super.speak();System.out.print(Dog”);}}执行代码Petpet=newDog(京巴”);pet.speak();后输出的内容是哪项?()A.京巴B.京巴DogC.nullD.Dog京巴

publicclassPet{privateStringname;publicPet(Stringname){this.name=name;}publicvoidspeak(){System.out.print(name);}}publicclassDogextendsPet{publicDog(Stringname){super(name);}publicvoidspeak(){super.speak();System.out.print(Dog”);}}执行代码Petpet=newDog(京巴”);pet.speak();后输出的内容是哪项?()

A.京巴

B.京巴Dog

C.null

D.Dog京巴


相关考题:

执行以下代码后,下面哪些描述是正确的()publicclassStudent{privateStringname=Jema”;publicvoidsetName(Stringname){this.name=name;}publicStringgetName(){returnthis.name;}publicstaticvoidmain(String[]args){Students;System.out.println(s.getName());}}A.输出nullB.第10行编译报错C.第11行编译报错D.输出Jema

publicclassEmployee{privateStringname;publicEmployee(Stringname){this.name=name;}publicvoiddisplay(){System.out.print(name);}}publicclassManagerextendsEmployee{privateStringdepartment;publicManager(Stringname,Stringdepartment){super(name);this.department=department;}publicvoiddisplay(){System.out.println(super.display()+”,”+department);}}执行语句newManager(smith”,”SALES”)后程序的输出是哪项?()A.smith,SALESB.null,SALESC.smith,nullD.null,null

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publicclassEmployee{privateStringname;publicEmployee(Stringname){this.name=name;}publicStringgetName(){returnname;}}publicclassManagerextendsEmployee{privateStringdepartment;publicManager(Stringname,Stringdepartment){this.department=department;super(name);(应于上一行掉位置)System.out.println(getName());}}Super的位置是否在方法的首行执行语句newManager(smith”,”SALES”)后程序的输出是哪项?()A.smithB.nullC.SALESD.编译错误

类Teacher:classTeacher{Stringname;floatsalary;Teacher(Stringname){this.name=name;}Teacher(Stringname,floatsalary){this.name=name;this.salary=salary;}}执行语句Teachert=newTeacher(Tom”,2000.0f);后,字段salary的值是哪一项?()A.2000.0fB.0.0fC.null;D.2000

publicclassPerson{2.privateStringname;3.publicPerson(Stringname){this.name=name;}4.publicbooleanequals(Personp){5.returnp.name.equals(this.name);6.}7.}Whichistrue?() A.TheequalsmethoddoesNOTproperlyoverridetheObject.equalsmethod.B.Compilationfailsbecausetheprivateattributep.namecannotbeaccessedinline5.C.Toworkcorrectlywithhash-baseddatastructures,thisclassmustalsoimplementthehashCodemethod.D.WhenaddingPersonobjectstoajava.util.Setcollection,theequalsmethodinline4willpreventduplicates.

publicclassPlant{privateStringname;publicPlant(Stringname){this.name=name;}publicStringgetName(){returnname;}}publicclassTreeextendsPlant{publicvoidgrowFruit(){}publicvoiddropLeaves(){}}Whichistrue?() A.Thecodewillcompilewithoutchanges.B.ThecodewillcompileifpublicTree(){Plant();}isaddedtotheTreeclass.C.ThecodewillcompileifpublicPlant(){Tree();}isaddedtothePlantclass.D.ThecodewillcompileifpublicPlant(){this(”fern”);}isaddedtothePlantclass.E.ThecodewillcompileifpublicPlant(){Plant(”fern”);}isaddedtothePlantclass.

interface Playable {void play();}interface Bounceable {void play();}interface Rollable extends Playable, Bounceable {Ball ball = new Ball("PingPang");}class Ball implements Rollable {private String name;public String getName() {return name;}public Ball(String name) {this.name = name;}public void play() {ball = new Ball("Football");System.out.println(ball.getName());}}这个错误不容易发现。

Person p = new Person(“张三”,23);这条语句会调用下列哪个构造方法给属性进行初始化() A.public Person(){}B.public Person(String name,int age) { this.name = name; this.age = age; }C.public Person(int age,String name) { this.age = age; this.name = name; }D.public Person(String name) { this.name = name; }