A.peep
B.bark
C.meow
D.Compilation fails.
E.An exception is thrown at runtime.

A.Line 4 of class Target can be changed to return i++；
B.Line 2 of class Target can be changed to private int i = 1；
C.Line 3 of class Target can be changed to private int addOne（）{
D.Line 2 of class Target can be changed to private Integer i = 0；