Debugging is the process of identifying, analyzing, and fixing errors (bugs) in Java programs. In Advanced Java, debugging becomes critical when working with large codebases, multithreading, JDBC, servlets, and enterprise applications.
? Key Concepts
Compile-time vs Runtime errors
Logical errors and unexpected behavior
Stack trace analysis
Breakpoints and step execution
Logging for production debugging
? Syntax / Theory
Java provides multiple ways to debug applications:
Using print statements like System.out.println()
Using IDE debuggers (Eclipse, IntelliJ)
Analyzing Exception Stack Traces
Using Logging APIs such as java.util.logging
? Code Example(s)
? View Code Example
// Demonstrates a runtime exception and stack trace
public class DebugExample {
public static void main(String[] args) {
int a = 10;
int b = 0;
int result = a / b;
System.out.println(result);
}
}
? Live Output / Explanation
What Happens?
The program compiles successfully but fails during execution. Java throws an ArithmeticException because division by zero is not allowed. The stack trace points to the exact line causing the error.
? Interactive Debugger Simulation
Experience how a debugger steps through code line-by-line. Click Step Into to see variables change.
1 public static void main(String[] args) {
2 int total = 0;
3 for(int i=1; i<=3; i++) {
4 total = total + i;
5 System.out.println(total);
6 }
7 }
Variables Watch
Application stopped.
Console Output
? Tips & Best Practices
Always read stack traces from top to bottom
Use meaningful variable names for easier tracing
Prefer logging instead of print statements in real applications
Debug one issue at a time to avoid confusion
? Try It Yourself
Modify the value of b and re-run the program
Add multiple print statements to track execution flow
Use an IDE debugger and set a breakpoint on the division line