题目：

解答：

Program 1：

(1) Fault: ‘for(int i=x.length-1;i>0;i--)’. It should be “i>=0”.

(2) X=[],y=2.

　　Expected=NullPointerException.

　　Output=NullPointerException

(3) X=[2,3,5],y=3.

　　Expected=1

　　Output=1

(4) X=[1,3,5],y=2.

　　Expected=-1

　　Output=-1

Program 2：

(1) Fault: The for-loop should be:

　　for(int i=x.length-1;i>=0;i--)

(2)It’s impossible.

(3) X=[]

　　Expected=NullPointerException.

　　Output=NullPointerException

(4)x=[0,1,2]

　　Expected=0

　　Output=0

Summery：

fault - a cause of the error (mistake in coding)

error - incorrect state that may lead to failure

failure - deviation of the service from the correct service