Checked and Unchecked Exceptions

In Java, exceptions are categorized into two main types: checked and unchecked exceptions.

Checked Exceptions

• Definition: These are exceptions that are checked at compile-time. The compiler ensures that these exceptions are either caught using a try-catch block or declared in the method signature using the throws keyword.
• Examples: IOException, SQLException, ClassNotFoundException.
• Usage: Checked exceptions typically represent conditions that a reasonable application might want to catch, such as file I/O errors or database access issues.

Unchecked Exceptions

• Definition: These exceptions are not checked at compile-time. They include RuntimeException and its subclasses, as well as Error and its subclasses.
• Examples: NullPointerException, ArrayIndexOutOfBoundsException, ArithmeticException.
• Usage: Unchecked exceptions usually indicate programming errors, such as logic mistakes or improper use of an API. They are often not intended to be caught or handled explicitly.

Key Differences

• Handling Requirement: Checked exceptions must be explicitly handled or declared, while unchecked exceptions do not have this requirement.
• Hierarchy: Checked exceptions extend Exception (excluding RuntimeException), whereas unchecked exceptions extend RuntimeException or Error.

References:

• Checked vs Unchecked Exceptions in Java - GeeksforGeeks
• Checked or Unchecked Exceptions? - Jenkov.com
• Exception Handling in Java
• Checked and Unchecked Exceptions in Java - Baeldung
• Java Checked vs Unchecked Exceptions - HowToDoInJava