现自: 1. interface Color { } 2. interface Weight { } 3. //insert code here 和以下足六个声明: class Boat extends Color, extends Weight { } class Boat extends Color and Weight { } class Boat extends Color, Weight { } class Boat implements Color, implements Weight { } class Boat implements Color and Weight { } class Boat implements Color, Weight { } 分别插入到第3行,有多少行可以编译? ()
第1题:
Which three demonstrate an “is a” relationship?()
第2题:
现在有两个类A、B,以下描述中表示B继承自A的是()
第3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?()
第4题:
Which the two demonstrate an “is a” relationship?()
第5题:
Which two demonstrate an “is a” relationship?()
第6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?()
第7题:
public interface Person { } public class Employee extends Person { }
public interface Shape { } public class Employee extends Shape { }
public interface Color { } public class Employee extends Color { }
public class Species { } public class Animal (private Species species;)
interface Component { } Class Container implements Component ( Private Component[ ] children; )
第8题:
0
1
2
3
第9题:
只有s1
只有s3
只有s1和s3
只有s1和s4
第10题:
int foo() { /* more code here */ }
void foo() { /* more code here */ }
public void foo() { /* more code here */ }
private void foo() { /* more code here */ }
protected void foo() { /* more code here */ }
第11题:
public class X { } public class Y extends X { }
public interface Shape { } public interface Rectangle extends Shape{ }
public interface Color { } public class Shape { private Color color; }
public interface Species { } public class Animal { private Species species; }
public class Person { } public class Employee { public Employee(Person person) { }
interface Component { } class Container implements Component { private Component[] children; }
第12题:
0
1
2
3
第13题:
interface Data { public void load(); } abstract class Info { public abstract void load(); } Which class correctly uses the Data interface and Info class?()
第14题:
定义一个类名为"MyClass.java"的类,并且该类可被一个工程中的所有类访问,那么该类的正确声明应为()。
第15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?()
第16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?()
第17题:
10. interface Foo {} 11. class Alpha implements Foo {} 12. class Beta extends Alpha {} 13. class Delta extends Beta { 14. public static void main( String[] args) { 15. Beta x = new Beta(); 16. // insert code here 17. } 18. } Which code, inserted at line 16, will cause a java.lang.ClassCastException?()
第18题:
现有: 1. interface Animal { 2. void eat(); 3. } 4. 5. // insert code here 6. 7. public class HouseCat implements Feline { 8. public void eat() { } 9. } 和以下三个接口声明: interface Feline extends Animal { } interface Feline extends Animal { void eat(); } interface Feline extends Animal { void eat() { } } 分别插入到第 5 行,有多少行可以编译?()
第19题:
Alpha a = x;
Foo f= (Delta)x;
Foo f= (Alpha)x;
Beta b = (Beta)(Alpha)x;
第20题:
public interface Person {} Public class Employee extends Person {}
public interface Shape {} public interface Rectangle extends Shape {}
public interface Color {} public class Shape { private Color color; }
public class Species {} public class Animal { private Species species; }
interface Component {} Class Container implements Component {private Component [] children;
第21题:
0
1
2
3
第22题:
0
1
2
3
第23题:
public class Employee extends Info implements Data { public void load() { /*do something*/ } }
public class Employee implements Info extends Data { public void load() { /*do something*/ } }
public class Employee extends Info implements Data { public void load() { /*do something */ } public void Info.load() { /*do something*/ } }
public class Employee implements Info extends Data { public void Data.load() { /*dsomething */ } public void load() { /*do something */ } }
public class Employee implements Info extends Data { public void load() { /*do something */ } public void Info.load(){ /*do something*/ } }
public class Employee extends Info implements Data{ public void Data.load() { /*do something*/ } public void Info.load() { /*do something*/ } }