For the Program1,

　　For Question1: 

　　The fault is that in the loop condition, ' i ' should be not less than(>=) 0 rather than just greater than(>) 0. This will result in the problem that if the target is just in the position 0 and then the program cannot return the correct answer.

　　The original one is like this,　　

　　　　for (int i=x.length-1; i > 0; i--)

　　However, it should be like this,

　　　　for (int i=x.length-1; i >= 0; i--)

　　For Question2:

　　Test: x = [2], y = 2　

　　In this test case, the length of the ' x ' is just 1 and then it cannot suit the condition of the loop. In the other word, it will not go into the loop and then the program will return -1. And this is not the correct answer obversely.

　　For Question3:

　　Test: x = [3,2,5], y = 2

　　In this test case, the original program will not occur a failure because the target is not in the position 0. As a result, this will not make a mistake even if it has the reachability.

　　But it will be in a error state.

　　For Question4:

　　Test: x=[2, 2, 5]; y = 2

　　Expected = 1

　　As a result, the program do not check the x[0] and this is an error condition but the answer is correct and this is not a failure.

 

For the Program2,

　　For Question1:

　　The fault is that the origenal program return the first 0 that occurs in ' x ' but not the last.

　　The original one is like this,　　

　　　　for (int i = 0; i < x.length; i++)

　　However, it should be like this,

　　　　for (int i=x.length-1; i >= 0; i--)

　　For Question2:

　　I think it is impossible or maybe ' x ' is an empty array (that may throw a NullPointerException). And then this may not execute the fault.

　　For Question3:

　　Test case: x = [3]

　　Or maybe it is impossible.

　　For Question4:

　　Test: x = [0,1,1] return is 0 and this is right.

　　Because the 0 is the only one in the array and then the first and the last is the same.