Q 36 - Checked & Unchecked Exception

[AmjustGettingStarted]

What is the difference between checked and unchecked exceptions?

[HARSHITH-MV]

✅ Checked Exceptions

These are checked at compile time, meaning the compiler forces you to handle them explicitly.

• Examples: IOException, SQLException, FileNotFoundException
• Must be caught or declared with throws in method signature.
• Common in scenarios where failure is expected and recoverable, like reading a file or accessing a database.

try {
    FileReader reader = new FileReader("data.txt");
} catch (FileNotFoundException e) {
    e.printStackTrace();
}

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🚫 Unchecked Exceptions

These are not checked at compile time—you can handle them, but the compiler won’t demand it.

• Examples: NullPointerException, ArrayIndexOutOfBoundsException, IllegalArgumentException
• Usually caused by programming logic errors.
• Often indicate bugs, not recoverable conditions.

int[] numbers = {1, 2, 3};
System.out.println(numbers[5]); // Throws ArrayIndexOutOfBoundsException

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🔍 Quick Comparison

Feature	Checked Exception	Unchecked Exception
Checked by Compiler?	✅ Yes	❌ No
Needs try-catch or throws	✅ Required	❌ Optional
Typical Cause	External issues (files, I/O)	Logic errors (bugs)
Examples	IOException, ParseException	NullPointerException, ArithmeticException

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