Description
Objective
In this lab, you will become familiar with debuggers.
Working individually you will debug a few programs. While the defects in the programs of this lab
may not be complicated, use the time to become familiar with how your debugger works before you
are faced with complex code.
Do not resort to debugging in this lab using print statements.
Preparation
• Download HfxDonairExpress.java, Ackermann.java, and LinkedListTest.java from Lab 2
in Brightspace
Resources
• A debugger which allows inspecting variables, breakpoints, stack traces
Procedure
Lab steps
1. Run HfxDonairExpress on some inputs. You do not need to check invalid input.
2. Examine the output until you find an incorrect value.
3. Set a breakpoint at the start of the program.
4. Select a defect in the program.
5. Run your program in the debugger and step through the program to identify where the defect
happens in the code.
6. Determine what could fix the defect.
7. Implement your fix and re-test to ensure that the defect is fixed.
8. Repeat until no defects remain.
Repeat these steps for Ackermann.java and LinkedListTest.java.
1
Analysis
What strategy or strategies for debugging are most effective for you?
What makes them effective?
For which conditions of the code will your strategies be effective or ineffective?
How can a debugger support your strategies?
Reporting
1. In one file, list
• The cause of the defects that you found.
• The approach that let you locate the defect.
• The approximate amount of time it took you to locate the defect.
• The answers from the questions in the Analysis section of the lab.
2. Generate a PDF from the document.
3. Submit the PDF and your Java files in Brightspace in the Lab/Lab 2 section of the course page
in Brightspace.
Assessment
The assessment will be on a letter grade and will reflect how well you are demonstrating that you
are using and understanding debugging strategies and support tools like the debugger. I am more
concerned with your familiarity with the debugging process than on finding and fixing every bug in
the lab code.
2
Letter grade Defects detected and
fixed
Strategies to locating
the defects
Analysis thoughts on
effective debugging
strategies (higher
weight)
Analysis on how
the debugger supports the debugging
strategies
A
(Excellent) All defects fixed with
minimal code changes
Different strategies
for the types of
defects
Demonstrates an
understanding of the
benefits and limitations of different
strategies
Connects the debugger features with the
strategies. More than
one feature might
support one strategy
B
(Good) All defects identified
and 75% of them are
fixed
Has two strategies for
debugging
Demonstrates an appreciation for different debugging strategies in different cases
Knows how a set
of debugger features
supports one strategy
C
(Satisfactory) All defects identified
and a start is made on
fixing them
Used the debugger
to trace through the
code to find bugs
Has at least one strategy other than print
statements in mind
and knows when to
use it or to abandon
it
Can see how one debugger feature helps
with debugging
D
(Marginal Pass) Some defects identified and fixed
Resorted to some
print statements to
detect bugs
Repeating what we
might find on the web
about debugging but
not showing that they
understand when to
use what
Knows how the debugger can at least
avoid debugging with
a pile of print statements
F
(Inadequate) Little clarity on
what’s wrong with
the programs
Fell to fixing code by
perturbing it until it
worked
Little understanding
of how to approach
debugging in the large
context
Unsure on how the
debugger will help
with debugging
3
