CSCE 155
Spring 2005
Lab 4 - Debugging Java Programs
Student Handout
1. Lab Objectives
Following the lab you should be able to:
Describe the differences between syntax, semantic (logic), and runtime errors.
Debug a simple program using print statements.
Use the Integrated Debugger to debug a simple Java program.
2. Prior to the laboratory
Review the laboratory handout
Read “The Integrated Debugger” at http://www.jgrasp.org/tutorials/07_Debugger.pdf
Read an “Introduction to Program Testing & Debugging”,
http://www.engin.umich.edu/class/eecs100/Assignments/introDebug.pdf
Read “The 10 Truths of Debugging”, http://www.duke.edu/web/cps001/notes/Debugging.pdf
3. Topics
Topics Covered in Lab
Types of errors: 1) syntax 2) semantic 3) runtime
Basic debugging techniques
Java compiler messages
source code review
print statements
debugger
4. Activities/Exercises
1. Exploring the Integrated Debugger functionality.
2. Using print statements to debug a program.
3. Extra practice debugging Java programs.
Activity 1: Exploring the Integrated Debugger functionality
Download CountCharacters.java from the course website.
The CountCharacters class prints the number of vowels, blank characters, and the number of
numeric characters contained in a string entered from the keyboard.
Compile and execute CountCharacters.java using the string:
o Spring Semester Year 2005
Record the results of executing CountCharacters on your worksheet (Activity 1, Question 1).
Set breakpoint #1 in the main() method on the line:
inputValue = count.getInput();
Set breakpoint #2 in the main() method on the line:
count.processString(inputValue);
Set breakpoint #3 in the processString() method on the first line of the for loop:
currentString = inputString.substring(i,i+1);
Make sure the debug option is selected under the Compiler command in the CSD window.
Run the program by clicking on the ladybug button. (Run debugger on current file.)
Date:11/28/2020 1
