Java.Core.What is the difference between checked and unchecked exceptions?

Here’s a clear breakdown of the difference between checked and unchecked exceptions in Java:

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✅ Checked Exceptions

Definition

These are exceptions that the compiler forces you to handle — either by using a try-catch block or by declaring them in the method signature using throws.

Examples

• IOException
• SQLException
• FileNotFoundException

Key Features

• Checked at compile time.
• The compiler checks that your code either handles these exceptions (with try-catch) or explicitly declares them (with throws).
• Typically used for recoverable situations — things you can anticipate and handle gracefully, like file not found, database issues, etc.

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❌ Unchecked Exceptions

Definition

These are exceptions that the compiler does not force you to handle. They usually indicate programming bugs (logic errors) rather than recoverable conditions.

Examples

• NullPointerException
• ArrayIndexOutOfBoundsException
• IllegalArgumentException

Key Features

• Checked at runtime.
• No need to catch or declare them.
• Usually caused by flaws in code logic — like accessing a null reference or an out-of-bounds index.

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Quick Summary Table

	Checked Exception	Unchecked Exception
Checked by Compiler?	✅ Yes	❌ No
Declared in method signature?	✅ Required	❌ Not required
Type	Recoverable	Programming bug
Examples	IOException, SQLException	NullPointerException, ArrayIndexOutOfBoundsException

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A Rule of Thumb

• Checked Exceptions = External problems (files, network, DB)
• Unchecked Exceptions = Internal problems (bugs, logic errors)