单项选择题
A. Compilation fails because of an error in line 13.
B. A ClassCastException is thrown at runtime.
C. 1 2 3
D. Compilation fails because of an error in line 14.
E. Compilation fails because of an error in line 12.
多项选择题 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？（）
单项选择题 Given： What is the result？ （）