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现有: 1 Interface F{} 2 class A implements F{} 3 class B extends A{} 4 class C extends B{ 5 public static void main(String[] args){ 6 B b=new B(); 7 //inSert C0de here 8 } 9 } 下列哪行代码插入到第7行,将抛出java.lang.ClassCaseException异常()
- A、 A a=b;
- B、 F f= (C)b;
- C、 F f= (A)b;
- D、 B bb= (B)(A)b;
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更多 “ 现有: 1 Interface F{} 2 class A implements F{} 3 class B extends A{} 4 class C extends B{ 5 public static void main(String[] args){ 6 B b=new B(); 7 //inSert C0de here 8 } 9 } 下列哪行代码插入到第7行,将抛出java.lang.ClassCaseException异常()A、 A a=b;B、 F f= (C)b;C、 F f= (A)b;D、 B bb= (B)(A)b;” 相关考题
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现有: 1. interface Animal f 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? A、 0B、 1C、 2D、 3
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现有: 1. class HorseRadish { 2. // insert code here 3. protected HorseRadish(int x) { 4. System.out.println("bok choy"); 5. } 6. } 7. class Wasabi extends HorseRadish { 8. public static void main(String [] args) { 9. Wasabi w = new Wasabi(); 10. } 11. } 分别插入到第 2 行,哪两项允许代码编译并产生"bok choy" 输出结果?() A、 // just a commentB、 protected HorseRadish() { }C、 protected HorseRadish() { this(42);}D、 protected HorseRadish() { new HorseRadish (42);}
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1. class HorseRadish { 2. // insert code here 3. protected HorseRadish(int x) { 4. System.out.println("bok choy"); 5. } 6. } 7. class Wasabi extends HorseRadish { 8. public static void main(String [] args) { 9. Wasabi w = new Wasabi(); 10. } 11. } 分别插入到第 2 行,哪两项允许代码编译并产生"bok choy" 输出结果?() A、 // just a commentB、 protected HorseRadish() { }C、 protected HorseRadish() { this(42);}D、 protected HorseRadish() { new HorseRadish (42);}
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Which statements, when inserted at the indicated position in the following code, will cause a runtime exception when attempting to run the program?() class A {} class B extends A {} class C extends A {} public class Q3ae4 { public static void main(String args[]) { A x = new A(); B y = new B(); C z = new C(); // insert statement here } } A、x = y;B、z = x;C、y = (B) x;D、z = (C) y;E、y = (A) y;
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1. class Alpha { void m1() {} } 2. class Beta extends Alpha { void m2() { } } 3. class Gamma extends Beta { } 4. 5. class GreekTest { 6. public static void main(String [] args) { 7. a Alpha [] a = {new Alpha(), new Beta(), new Gamma() }; 8. for(Alpha a2 : a) { 9. a2.m1(); 10. if (a2 instanceof Beta || a2 instanceof Gamma) 11. //insert code here 12. } 13. } 14. } 哪一行代码插入到第11行,将编译但是会在运行时产生异常?() A、 a2.m2();B、 ((Beta)a2).m2();C、 ((Alpha)a2).m2();D、 ((Gamma)a2).m2();
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现有: 1. import java.util.*; 2. 3. Class FindStuff { 4.public static void main (String[]args) { 5, //insert code here 6. c.put ("X", 123); 7. } 8. } 分别插入到第5行,哪三行允许代码编译?() A、 Map c= new SortedMap();B、 HashMap c= new HashMap();C、 HashMap c= new Hashtalole();D、 SortedMap c= new TreeMap();E、 ArrayList c= new ArrayList();F、 MaD c = new LinkedHashMap();
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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?() A、 Alpha a = x;B、 Foo f= (Delta)x;C、 Foo f= (Alpha)x;D、 Beta b = (Beta)(Alpha)x;
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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
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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?() A、 0B、 1C、 2D、 3
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多选题现有: class HorseRadish { //insert code here protected HorseRadish (int x) { System.out.println ("bok choy"); } } class Wasabi extends HorseRadish { public static void main (String [] args){ Wasabi w- new Wasabi(); } } 分别插入到第2行,哪两项允许代码编译并产生”bok choy”输出结果()Aprotected HorseRadish() {this (42);}Bprotected HorseRadish() {}C//just a commentDprotected HorseRadish() { new HorseRadish (42);}
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单选题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?()A
Alpha a = x;B
Foo f= (Delta)x;C
Foo f= (Alpha)x;D
Beta b = (Beta)(Alpha)x;
考题
多选题现有: 1. class HorseRadish { 2. // insert code here 3. protected HorseRadish(int x) { 4. System.out.println("bok choy"); 5. } 6. } 7. class Wasabi extends HorseRadish { 8. public static void main(String [] args) { 9. Wasabi w = new Wasabi(); 10. } 11. } 分别插入到第 2 行,哪两项允许代码编译并产生"bok choy" 输出结果?()A// just a commentBprotected HorseRadish() { }Cprotected HorseRadish() { this(42);}Dprotected HorseRadish() { new HorseRadish (42);}
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多选题1. class HorseRadish { 2. // insert code here 3. protected HorseRadish(int x) { 4. System.out.println("bok choy"); 5. } 6. } 7. class Wasabi extends HorseRadish { 8. public static void main(String [] args) { 9. Wasabi w = new Wasabi(); 10. } 11. } 分别插入到第 2 行,哪两项允许代码编译并产生"bok choy" 输出结果?()A// just a commentBprotected HorseRadish() { }Cprotected HorseRadish() { this(42);}Dprotected HorseRadish() { new HorseRadish (42);}
考题
单选题1. import java.util.*; 2. class SubGen { 3. public static void main(String [] args) { 4. //insert code here 5. } 6. } class Alpha { } class Beta extends Alpha { } class Gamma extends Beta { } 和四段代码片段: s1. ArrayList〈? extends Alpha〉 list1 = new ArrayList〈Gamma〉(); s2. ArrayList〈Alpha〉 list2 = new ArrayList〈? extends Alpha〉(); s3. ArrayList〈? extends Alpha〉 list3 = new ArrayList〈? extends Beta〉(); s4. ArrayList〈? extends Beta〉 list4 = new ArrayList〈Gamma〉(); ArrayList〈? extends Alpha〉 list5 = list4; 哪些片段分别插入到第4行,可允许代码编译?()A
只有s1B
只有s3C
只有s1和s3D
只有s1和s4
考题
单选题对于下列代码: 1) class Person { 2} public void printValue(int i, int j) {//... } 3} public void printValue(int i){//... } 4} } 5) public class Teacher extends Person { 6} public void printValue( ) {//... } 7} public void printValue(int i) {//...} 8} public static void main(String args[]){ 9} Person t = new Teacher( ); 10} t.printValue(10); 11} } 第10行语句将调用哪行语句?()A
line 2B
line 3C
line 6D
line 7
考题
单选题现有: 1. class Alpha { void m1() {} } 2. class Beta extends Alpha { void m2() { } } 3. class Gamma extends Beta { } 4. 5. class GreekTest { 6. public static void main(String [] args) { 7. Alpha [] a = {new Alpha(), new Beta(), new Gamma() }; 8. for(Alpha a2 : a) { 9. a2.m1(); 10. if (a2 instanceof Beta || a2 instanceof Gamma) 11. //insert code here 12. } 13. } 14. } 哪一行代码插入到第11行,将编译但是会在运行时产生异常?()A
a2.m2();B
((Beta)a2).m2();C
((Alpha)a2).m2();D
((Gamma)a2).m2();
考题
单选题现有: 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?()A
0B
1C
2D
3
考题
单选题现有: 1. interface Animal f 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?A
0B
1C
2D
3
考题
单选题Which statements, when inserted at the indicated position in the following code, will cause a runtime exception when attempting to run the program?() class A {} class B extends A {} class C extends A {} public class Q3ae4 { public static void main(String args[]) { A x = new A(); B y = new B(); C z = new C(); // insert statement here } }A
x = y;B
z = x;C
y = (B) x;D
z = (C) y;E
y = (A) y;
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