Given the following code:     1) class Parent {     2) private String name;     3) public Parent(){}     4) }  5) public class Child extends Parent {     6) private String department;  7) public Child() {}  8) public String getValue(){ return name; }    

题目

Given the following code:     1) class Parent {     2) private String name;     3) public Parent(){}     4) }  5) public class Child extends Parent {     6) private String department;  7) public Child() {}  8) public String getValue(){ return name; }     9) public static void main(String arg[]) {     10) Parent p = new Parent();     11) }  12) }  Which line will cause error?()   

  • A、 line 3
  • B、 line 6
  • C、 line 7
  • D、 line 8
  • E、 line 10
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相似问题和答案

第1题:

public class Person {  private String name, comment;  private int age;  public Person(String n, int a, String c) {  name = n; age = a; comment = c;  }  public boolean equals(Object o) {  if(! (o instanceof Person)) return false;  Person p = (Person)o;  return age == p.age && name.equals(p.name);  }  }  What is the appropriate definition of the hashCode method in class Person?() 

  • A、 return super.hashCode();
  • B、 return name.hashCode() + age * 7;
  • C、 return name.hashCode() + comment.hashCode() /2;
  • D、 return name.hashCode() + comment.hashCode() / 2 - age * 3;

正确答案:B

第2题:

public class Pet{     private String name;     public Pet(){  System.out.print(1);    }  public Pet(String name){        System.out.print(2);    } }  public class Dog extends Pet{     public Dog(String name){        System.out.print(3);    } }  执行new Dog(“棕熊”);后程序输出是哪项?() 

  • A、 23
  • B、 13
  • C、 123
  • D、 321

正确答案:B

第3题:

阅读下面代码 abstract class Person { public Person(String n) { name=n; } public______String getDescription(); public String getName() { return name; } private String name; } 在下画线处应填入的修饰符是

A.static

B.abstract

C.protected

D.final


正确答案:B

第4题:

public class Employee{       private String name;  public Employee(String name){           this.name = name;      }  public String getName(){         return name;      } }  public class Manager extends Employee{       private String department;  public Manager(String name,String department){          this.department = department;          super(name);  System.out.println(getName());      }  }  执行语句new Manager(“smith”,”SALES”)后程序的输出是哪项?() 

  • A、 smith
  • B、 null
  • C、 SALES
  • D、 编译错误

正确答案:D

第5题:

public class Employee{       private String name;  public Employee(String name){           this.name = name;      }  public void display(){         System.out.print(name);      } }  public class Manager extends Employee{       private String department;  public Manager(String name,String department){          super(name);  this.department = department;  }  public void display(){  System.out.println(super.display()+”,”+department);      } }  执行语句new Manager(“smith”,”SALES”)后程序的输出是哪项?() 

  • A、 smith,SALES
  • B、 null,SALES
  • C、 smith,null
  • D、 null,null
  • E、 编译错误

正确答案:E

第6题:

class Parent {     String one, two;  public Parent(String a, String b){     one = a;     two = b;    }  public void print(){ System.out.println(one); }    }  public class Child extends Parent {     public Child(String a, String b){     super(a,b);     }  public void print(){  System.out.println(one + " to " + two);     }  public static void main(String arg[]){     Parent p = new Parent("south", "north");     Parent t = new Child("east", "west");     p.print();     t.print();     }     }  Which of the following is correct?()

  • A、 Cause error during compilation. 
  • B、 south         east 
  • C、 south to north     east to west    
  • D、 south to north      east    
  • E、 south     east to west

正确答案:E

第7题:

public class Employee{   private String name;   public Employee(String name){   this.name = name;  }   public String getName(){   return name;  }  }   public class Manager extends Employee{   private String department;   public Manager(String name,String department){   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new Manager(“smith”,”SALES”)后程序的输出是哪项?()

  • A、 smith
  • B、 null
  • C、 SALES
  • D、 编译错误

正确答案:D

第8题:

为使下列代码正常运行,应该在下画线处填入的选项是( )。 abstract class person{ public Person(String n){ name=n: } Public String getDescription; public String getName{ return name; } private string name; }

A.static

B.private

C.abstract

D.final


正确答案:C
C。【解析】抽象类中的抽象方法可以只声明,定义延迟到其子类。

第9题:

public class Pet{     private String name;     public Pet(){  System.out.print(1);    }  public Pet(String name){        System.out.print(2);    } }  public class Dog extends Pet{     public Dog(){  System.out.print(4);    }  public Dog(String name){        super(name);  System.out.print(3);    } }  执行new Dog(“棕熊”);后程序输出是哪项?()  

  • A、 33
  • B、 13
  • C、 23
  • D、 123

正确答案:C

第10题:

public class Employee{   private String name;   public Employee(String name){   this.name = name;  }   public void display(){   System.out.print(name);  }  }   public class Manager extends Employee{   private String department;   public Manager(String name,String department){   super(name);   this.department = department;  }   public void display(){   System.out.println( super.display()+”,”+department);  }   }   执行语句new Manager(“smith”,”SALES”)后程序的输出是哪项?() 

  • A、 smith,SALES
  • B、 null,SALES
  • C、 smith,null
  • D、 null,null

正确答案:A

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