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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

参考答案

更多 “ 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 3B、 line 6C、 line 7D、 line 8E、 line 10” 相关考题
考题 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.staticB.abstractC.protectedD.final

考题 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.staticB.privateC.abstractD.final

考题 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;

考题 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

考题 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、 23B、 13C、 123D、 321

考题 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、 smithB、 nullC、 SALESD、 编译错误

考题 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,SALESB、 null,SALESC、 smith,nullD、 null,nullE、 编译错误

考题 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、 33B、 13C、 23D、 123

考题 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、 smithB、 nullC、 SALESD、 编译错误

考题 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,SALESB、 null,SALESC、 smith,nullD、 null,null

考题 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){   //这里隐藏了一句代码:super.pet();   System.out.print(3);  }   }   执行new Dog(“棕熊”);后程序输出是哪项?() A、 23B、 1 3C、 123D、 321

考题 public class Parent{     public void change(int x){} }  public class Child extends Parent{     //覆盖父类change方法  }  下列哪个声明是正确的覆盖了父类的change方法?() A、 protected void change(int x){}B、 public void change(int x, int y){}C、 public void change(String s){}D、 public void change(int x){}

考题 Given the uncompleted code of a class:     class Person {  String name, department;     int age;  public Person(String n){  name = n; }  public Person(String n, int a){  name = n;  age = a;  }  public Person(String n, String d, int a) {  // doing the same as two arguments version of constructor     // including assignment name=n,age=a    department = d;     }     }  Which expression can be added at the "doing the same as..." part of the constructor?() A、 Person(n,a);B、 this(Person(n,a));C、 this(n,a);D、 this(name,age);

考题 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){   //这里隐藏了一句代码:super.pet();   this();   System.out.print(3);  }  }   执行new Dog(“棕熊”);后程序输出是哪项?() A、 143B、 423C、 243D、 1134

考题 现有:  1. abstract class Color  {  2.protected abstract  String getRGB();     3.  }     4.  5. public class Blue extends Color  {     6.    //insert code here      7.  }  和四个声明:  public String getRGB()  {  return "blue";  }      String getRGB()  {  return  "blue";  )  private  String getRGB()  {  return  "blue";  }      protected String getRGB()  {  return "blue";  )      分别插入到第6行,有几个可以通过编译?()    A、  0B、  1C、  2D、  3

考题 public class Plant {  private String name;  public Plant(String name) { this.name = name; }  public String getName() { return name; }  }  public class Tree extends Plant {  public void growFruit() { }  public void dropLeaves() { }  }  Which is true?() A、 The code will compile without changes.B、 The code will compile if public Tree() { Plant(); } is added to the Tree class.C、 The code will compile if public Plant() { Tree(); } is added to the Plant class.D、 The code will compile if public Plant() { this(”fern”); } is added to the Plant class.E、 The code will compile if public Plant() { Plant(”fern”); } is added to the Plant class.

考题 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){        this();  System.out.print(3);    } }  执行new Dog(“棕熊”);后程序输出是哪项?()  A、 143B、 423C、 243D、 1134

考题 public class Employee{   private String name;   public Employee(String name){   this.name = name;  }   public String getName(){   return name;  }  }   public class Manager extends Employee{   public Manager(String name){   System.out.println(getName());  }  }   执行语句new Manager(“smith”)后程序的输出是哪项?() A、 smithB、 nullC、 编译错误D、 name

考题 public class Parent {     int change() {…}     }  class Child extends Parent {     }  Which methods can be added into class Child?()    A、 public int change(){}B、 int chang(int i){}C、 private int change(){}D、 abstract int chang(){}

考题 public class NamedCounter {  private final String name;  private int count;  public NamedCounter(String name) { this.name = name; }  public String getName() { return name; }  public void increment() { coount++; }  public int getCount() { return count; } public void reset() { count = 0; } }  Which three changes should be made to adapt this class to be used safely by multiple threads? ()A、 declare reset() using the synchronized keywordB、 declare getName() using the synchronized keywordC、 declare getCount() using the synchronized keywordD、 declare the constructor using the synchronized keywordE、 declare increment() using the synchronized keyword

考题 单选题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){        this();  System.out.print(3);    } }  执行new Dog(“棕熊”);后程序输出是哪项?()A  143B  423C  243D  1134

考题 单选题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  23B  13C  123D  321

考题 单选题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,SALESB  null,SALESC  smith,nullD  null,nullE  编译错误

考题 单选题public class Plant {  private String name;  public Plant(String name) { this.name = name; }  public String getName() { return name; }  }  public class Tree extends Plant {  public void growFruit() { }  public void dropLeaves() { }  }  Which is true?()A  The code will compile without changes.B  The code will compile if public Tree() { Plant(); } is added to the Tree class.C  The code will compile if public Plant() { Tree(); } is added to the Plant class.D  The code will compile if public Plant() { this(”fern”); } is added to the Plant class.E  The code will compile if public Plant() { Plant(”fern”); } is added to the Plant class.

考题 单选题public class Employee{       private String name;  public Employee(String name){           this.name = name;      }  public String getName(){         return name;      } }  public class Manager extends Employee{       public Manager(String name){          System.out.println(getName());      } }  执行语句new Manager(“smith”)后程序的输出是哪项?()A  smithB  nullC  编译错误D  name

考题 单选题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 3B  line 6C  line 7D  line 8E  line 10

考题 单选题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){   //这里隐藏了一句代码:super.pet();   System.out.print(3);  }   }   执行new Dog(“棕熊”);后程序输出是哪项?()A  23B  1 3C  123D  321