What is the difference between checked and unchecked exceptions in Java?

Question

Accepted Answer

**Checked** — compile-time check. **Unchecked** — runtime exceptions.

**Checked exceptions:**
- Extend Exception (not RuntimeException).
- Must be caught or declared.
- Compile-time checking.

```java
// Checked exception
public void readFile() throws IOException {
    // Must declare or catch
    throw new IOException("File not found");
}

// Must handle
try {
    readFile();
} catch (IOException e) {
    e.printStackTrace();
}
```

**Unchecked exceptions:**
- Extend RuntimeException.
- No compile-time checking.
- Optional to catch.

```java
// Unchecked exception
public void divide(int a, int b) {
    if (b == 0) {
        throw new ArithmeticException("Division by zero");
    }
}
```

**Examples:**
- **Checked:** IOException, SQLException.
- **Unchecked:** NullPointerException, ArrayIndexOutOfBounds.

Java: What is the difference between checked and unchecked exceptions in Java?