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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、  0
  • B、  1
  • C、  2
  • D、  3

参考答案

更多 “ 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” 相关考题
考题 下列哪个类声明是正确的?A.abstract class G2 extends superClassl,superClass2{……}B.abstract public class classmates{……}C.public final class NewClass extends superClass implements Interfacel{……}D.public abstract class String{……}

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 下列哪个类声明是正确的? ( )A.abstract class G2 extends superClass1,superClass2{...}B.abstract public class classmates{...}C.public final class NewClass extends superClass implemnets Interface1{...}D.public abstract class String{...}

考题 下列哪个类声明是正确的? ( )A.abstract class G2 extends superClass1, superClass2 {…}B.abstract public class classmates{…}C.public final class NewClass extends superClass implemnets Interfacel{…}D.public abstract class String{…}

考题 1. class BaseClass {  2. private float x = 1.of;  3. protected float getVar() { return x; }  4. }  5. class SubClass extends BaseClass {  6. private float x = 2.Of;  7. // insert code here 8. }   Which two are valid examples of method overriding when inserted at line 7?() A、 float getVar() { return x; }B、 public float getVar() { return x; }C、 public double getVar() { return x; }D、 protected float getVar() { return x; }E、 public float getVar(float f) { return f; }

考题 1. public class Employee {  2. String name;  3. double baseSalary;  4. Employee(String name, double baseSalary) {  5. this.name = name;  6. this.baseSalary = baseSalary;  7. }  8. }  And:  1. public class Salesperson extends Employee { 2. double commission;  3. public Salesperson(String name, double baseSalary,  4. double commission) {  5. // insert code here  6. } 7. }  Which code, inserted at line 7, completes the Salesperson constructor?() A、 this.commission = commission;B、 superb(); commission = commission;C、 this.commission = commission; superb();D、 super(name, baseSalary); this.commission = commission;E、 super(); this.commission = commission;F、 this.commission = commission; super(name, baseSalary);

考题 1. public interface A {  2. public void doSomething(String thing);  3. }  1. public class AImpl implements A {  2. public void doSomething(String msg) { }  3. }  1. public class B {  2. public A doit() {  3. // more code here  4. }  5.  6. public String execute() { 7. // more code here  8. }  9. }  1. public class C extends B {  2. public AImpl doit() {  3. // more code here  4. }  5.  6. public Object execute() {  7. // more code here  8. }  9. }  Which statement is true about the classes and interfaces in the exhibit?() A、 Compilation will succeed for all classes and interfaces.B、 Compilation of class C will fail because of an error in line 2.C、 Compilation of class C will fail because of an error in line 6.D、 Compilation of class AImpl will fail because of an error in line 2.

考题 class Sock2 {   String color;   public boolean equals(Object o) {   return color.equals(((Sock2)o).color);   } }   class TestSocks {   public static void main(String [] args) {   Sock2 s1 = new Sock2(); s1.color = "blue";   Sock2 s2 = new Sock2(); s2.color = "blue";   if (s1.equals(s2)) System.out.print("equals ");   if (s1 == s2) System.out.print("== ");   }   }   结果为:()      A、==B、equalsC、equals ==D、无结果输出

考题 现有:  1. abstract class Color2  {      2.    //insert code here      3.  }      4.  5. public class Blue2 extends Color2  {  6.public  String getRGB()  {  return  "blue";  }      7.  }  和4个声明:  public abstract  String getRGB();     abstract  String getRGB();  private abstract  String getRGB();      protected abstract String getRGB();  分别插入到第2行,有多少行可以编译?()     A、  0B、  1C、  2D、  3

考题 public class OuterClass {   private double d1 1.0;   //insert code here   }   You need to insert an inner class declaration at line2. Which two inner class declarations are valid?()A、 static class InnerOne {  public double methoda() {return d1;}  }B、 static class InnerOne {  static double methoda() {return d1;}  }C、 private class InnerOne {  public double methoda() {return d1;}  }D、 protected class InnerOne {  static double methoda() {return d1;}  }E、 public abstract class InnerOne {  public abstract double methoda();  }

考题 现有:   1. class Synapse {    2.    protected int gap() { return 7; }    3. }   4.     5. class Creb extends Synapse {    6.   // insert code here   7. }    分别插入到第 6 行,哪三行可以编译?()A、 int gap() { return 7; }B、 public int gap() { return 7; }C、 private int gap(int x) { return 7; }D、 protected Creb gap() { return this; }E、 public int gap() { return Integer.getInteger ("42"); }

考题 class Sock {  String size;  String color;  public boolean equals(Object o) {  Sock s = (Sock) o;  return color.equals(s.color);   }  // insert code here  }  哪两个满足 hashCode 的约定?()A、public int hashCode() { return 343; }B、public int hashCode() { return size.hashCode (); }C、public int hashCode() { return color.hashCode (); }D、public int hashCode() { return (int) (Math.random() * 1000);

考题 1. class A {  2. public String toString ()  {  3. return “4”;  4. }  5. }  6. class B extends A {  7. public String toString ()   {  8. return super.toString()  + “3”;  9. }  10. }  11. public class Test {  12.   public static void main(String[]args)  {  13.      System.out.printIn(new B());  14.      }  15. }    What is the result?()  A、 Compilation succeeds and 4 is printed.B、 Compilation succeeds and 43 is printed.C、 An error on line 9 causes compilation to fail.D、 An error on line 14 causes compilation to fail.E、 Compilation succeeds but an exception is thrown at line 9.

考题 1. class Synapse {   2. protected int gap() { return 7; }   3. }   4.   5. class Creb extends Synapse { 6. // insert code here  7. }  分别插入到第 6 行,哪三行可以编译?()A、 int gap() { return 7; }B、 public int gap() { return 7; }C、 private int gap(int x) { return 7; }D、 protected Creb gap() { return this; }E、 public int gap() { return Integer.getInteger ("42"); }

考题 现有:  interface Animal {       void eat () ;       }       //insert code here       public class HouseCat extends Feline {       public void eat() { }       }  和五个申明  abstract class Feline implements Animal { }  abstract  class  Feline  implements  Animal  {  void eat () ;  }  abstract class Feline implements Animal { public void eat();}  abstract class Feline implements Animal { public void eat() {}  }  abstract class Feline implements Animal { abstract public void eat();} 结果为:()      A、1B、2C、3D、4

考题 package sun.scjp;  public enum Color { RED, GREEN, BLUE }  package sun.beta;  // insert code here  public class Beta {  Color g = GREEN;  public static void main( String[] argv)  { System.out.println( GREEN); }  }  The class Beta and the enum Color are in different packages.  Which two code fragments, inserted individually at line 2 of the Beta declaration, will allow this code to compile?()A、 import sun.scjp.Color.*;B、 import static sun.scjp.Color.*;C、 import sun.scjp.Color; import static sun.scjp.Color.*;D、 import sun.scjp.*; import static sun.scjp.Color.*;E、 import sun.scjp.Color; import static sun.scjp.Color.GREEN;

考题 1. abstract class Color2 {   2. //insert code here   3. }   4.   5. public class Blue2 extends Color2 {   6. public String getRGB() { return "blue"; }   7. }   和4个声明:   public abstract String getRGB();   abstract String getRGB();   private abstract String getRGB();   protected abstract String getRGB();   分别插入到第2行,有多少行可以编译?()  A、0B、1C、2D、3

考题 1. public class OuterClass {  2. private double d1 = 1.0;  3. // insert code here  4. }  Which two are valid if inserted at line 3?()  A、 static class InnerOne { public double methoda() { return d1; } }B、 static class InnerOne { static double methoda() { return d1; } }C、 private class InnerOne { public double methoda() { return d1; } }D、 protected class InnerOne { static double methoda() { return d1; } }E、 public abstract class InnerOne { public abstract double methoda(); }

考题 Given a class Repetition:  1. package utils;  2.  3. public class Repetition {  4. public static String twice(String s) { return s + s; }  5. }  and given another class Demo:  1. // insert code here 2.  3. public class Demo {  4. public static void main(String[] args) {  5. System.out.println(twice(”pizza”));  6. }  7. }  Which code should be inserted at line 1 of Demo.java to compile and run Demo to print“pizzapizza”?() A、 import utils.*;B、 static import utils.*;C、 import utils.Repetition.*;D、 static import utils.Repetition. *;E、 import utils.Repetition.twice();F、 import static utils.Repetition.twice;G、 static import utils.Repetition.twice;

考题 1. class A {  3. public String to String() {  4. return “4”;  5. }  6. }  7. class B extends A {  8. public String toString() { 9. return super.toString() + “3”;  10. }  11. }  12. public class Test {  13. public static void main (String[] args) {  14. System.out.printIn(new B()); 15. }  16. }   What is the result( )?   A、 Compilation succeeds and 4 is printed.B、 Compilation …………… is printed.C、 An error on line 9 cause compilation to fail.D、 An error on line 14 cause compilation to fail.E、 Compilation succeeds but an exception is thrown at line 9.

考题 现有:  1. interface Animal {  2. void eat();  3. }  4.  5. // insert code here  6.  7. public class HouseCat extends Feline {  8. public void eat() { }  9. }   和五个声明:  abstract class Feline implements Animal { }  abstract class Feline implements Animal { void eat(); }  abstract class Feline implements Animal { public void eat(); }  abstract class Feline implements Animal { public void eat() { } }  abstract class Feline implements Animal { abstract public void eat(); }  分别插入到第5行,有几个可以通过编译?() A、0B、1C、2D、3

考题 public class Car {  private int wheelCount;  private String vin;  public Car(String vin) {  this.vin = vin;  this.wheelCount = 4;  }  public String drive() {  return “zoom-zoom”;  }  public String getInfo() {  return “VIN: “+ vin + “wheels: “+ wheelCount;  }  }  And:  public class MeGo extends Car {  public MeGo(String vin) {  this.wheelCount = 3;  }  }  What two must the programmer do to correct the compilation errors?()A、 insert a call to this() in the Car constructorB、 insert a call to this() in the MeGo constructorC、 insert a call to super() in the MeGo constructorD、 insert a call to super(vin) in the MeGo constructorE、 change the wheelCount variable in Car to protectedF、 change line 3 in the MeGo class to super.wheelCount = 3;

考题 多选题public class OuterClass {  private double d1  1.0;  //insert code here   }   You need to insert an inner class declaration at line2. Which two inner class declarations are valid?()Astatic class InnerOne {  public double methoda() {return d1;}  }Bstatic class InnerOne {  static double methoda() {return d1;} }Cprivate class InnerOne {  public double methoda() {return d1;} }Dprotected class InnerOne {  static double methoda() {return d1;} }Epublic abstract class InnerOne {  public abstract double methoda();  }

考题 单选题现有:  1. abstract class Color2  {      2.    //insert code here      3.  }      4.  5. public class Blue2 extends Color2  {  6.public  String getRGB()  {  return  "blue";  }      7.  }  和4个声明:  public abstract  String getRGB();     abstract  String getRGB();  private abstract  String getRGB();      protected abstract String getRGB();  分别插入到第2行,有多少行可以编译?()A   0B   1C   2D   3

考题 多选题class Sock {  String size;  String color;  public boolean equals(Object o) {  Sock s = (Sock) o;  return color.equals(s.color);   }  // insert code here  }  哪两个满足 hashCode 的约定?()Apublic int hashCode() { return 343; }Bpublic int hashCode() { return size.hashCode (); }Cpublic int hashCode() { return color.hashCode (); }Dpublic int hashCode() { return (int) (Math.random() * 1000);

考题 多选题1. public class OuterClass {  2. private double d1 = 1.0;  3. // insert code here  4. }  Which two are valid if inserted at line 3?()Astatic class InnerOne { public double methoda() { return d1; } }Bstatic class InnerOne { static double methoda() { return d1; } }Cprivate class InnerOne { public double methoda() { return d1; } }Dprotected class InnerOne { static double methoda() { return d1; } }Epublic abstract class InnerOne { public abstract double methoda(); }

考题 单选题现有:  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