Print Stack Trace of the Exception Example in Java

Introduction

Print stack trace of the Exception is a classic Java console program that demonstrates the concept with complete source code and sample output. Exceptions represent runtime errors; Java uses try-catch-finally to handle them safely.

This tutorial walks through the program line by line, explains how the logic works, and highlights best practices you can apply in your own code.

Syntax

<exception_name>.printStackTrace();

Print stack trace of the Exception Example Program

public class PrintStackTraceOfException {
    public static void main(String[] args) {
        try{
        String text = null;
        String subString = text.substring(3);
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}

Sample Output

java.lang.NullPointerException
	at learnjavaprograms.PrintStackTraceOfException.main(PrintStackTraceOfException.java:16)

When to use

Use this print stack trace of the exception example when learning or revising core Java syntax.

How it works

1. Execution begins in the main method — the JVM calls this method when you run the class.

2. String text = null; updates a variable used in the calculation or output.

3. String subString = text.substring(3); updates a variable used in the calculation or output.

4. Compare your console output with the sample output for Print stack trace of the Exception to confirm the program behaves correctly.

Best Practices

• Use meaningful variable and class names that describe their purpose.
• Compile and run the program locally — modify values to see how output changes.
• Read compiler errors carefully; they usually point to the exact line to fix.

Common Mistakes

• Copying code without understanding each line — practice by changing one statement at a time.
• Mismatching the public class name and the .java filename.
• Forgetting semicolons at the end of statements.