Given：
10. interface Jumper { public void jump（）； } ...  
20. class Animal {} ...  
30. class Dog extends Animal {  
31. Tail tail；  
32. }  
...  
40. class Beagle extends Dog implements Jumper{  
41. public void jump（） {} 
42. }  
...  
50. class Cat implements Jumper{  
51. public void jump（） {}  
52. }.
Which three are true？（）

多项选择题Click the Exhibit button.   Given： Which two statements are true if a NullPointerException is thrown on line 3 of class C？（）

A. The application will crash.
B. The code on line 29 will be executed.
C. The code on line 5 of class A will execute.
D. The exception will be propagated back to line 27.
E. The code on line 5 of class B will execute.

单项选择题Given： What is the result？ （）

A. A new Item object is created with the preferred value in the id attribute.
B. The attribute id in the Item object is modified to the new value.
C. Compilation fails.
D. An exception is thrown at runtime.
E. The attribute id in the Item object remains unchanged.

单项选择题Given： What is the result？（）

A. An exception is thrown at runtime.
B. int Long
C. Compilation fails.
D. Short Long

单项选择题Given： Which statement is true？（）

A. The cardID and limit variables break polymorphism.
B. The code demonstrates polymorphism.
C. The ownerName variable breaks encapsulation.
D. The setCardInformation method breaks encapsulation.
E. The class is fully encapsulated.

单项选择题Click the Exhibit button.   Given this code from Class B：   25. A a1 = new A（）；   26. A a2 = new A（）；   27. A a3 = new A（）；   28. System.out.println（A.getInstanceCount（））；   What is the result？（）

A. Compilation of class A fails.
B. Line 28 prints the value 3 to System.out.
C. Line 28 prints the value 1 to System.out.
D. Compilation fails because of an error on line 28.
E. A runtime error occurs when line 25 executes.