To solve this question, the user needs to understand the basic concept of method invocation and parameter passing.
First, let's go through the code. The Pass
class has a method main
which initializes an integer variable x
to 5. It then creates a new instance of the Pass
class and invokes the doStuff
method on that instance, passing in the value of x
. Finally, it prints out the value of x
.
The doStuff
method takes an integer parameter x
, prints out the value of x
incremented by 1, and then increments the parameter x
by 1.
Now, let's go through each option and explain why it is right or wrong:
A. Compilation fails - This option is incorrect. There are no syntax errors in the code.
B. An exception is thrown at runtime - This option is incorrect. There are no runtime errors in the code.
C. doStuffx = 6 main x = 6 - This option is incorrect. The value of x
in main
is still 5 after the doStuff
method is called because Java is a pass-by-value language. The parameter x
in doStuff
is a copy of the value of x
in main
, so incrementing the parameter does not affect the original value of x
.
D. doStuffx = 5 main x = 5 - This option is correct. The doStuff
method prints out the value of x
(which is 5) incremented by 1, resulting in the output "doStuff x = 6". However, the value of x
in main
remains 5 because Java is a pass-by-value language. Therefore, the final output is "main x = 5".
Therefore, the answer is: D. doStuffx = 5 main x = 5