> For the complete documentation index, see [llms.txt](https://boxlang.ortusbooks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://boxlang.ortusbooks.com/boxlang-language/reference/components/system/throw.md).

# Throw

Throws a developer-specified exception, which can be caught with a catch block.

## Component Signature

```
<bx:Throw message=[any]
type=[String]
detail=[String]
errorcode=[String]
extendedinfo=[any]
object=[Throwable] />
```

### Attributes

| Atrribute      | Type        | Required | Description                                                                                                                                                                                                            | Default |
| -------------- | ----------- | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------- |
| `message`      | `any`       | `false`  | Message that describes exception event                                                                                                                                                                                 |         |
| `type`         | `String`    | `false`  | The type of the exception                                                                                                                                                                                              |         |
| `detail`       | `String`    | `false`  | Description of the event                                                                                                                                                                                               |         |
| `errorcode`    | `String`    | `false`  | A custom error code that you supply                                                                                                                                                                                    |         |
| `extendedinfo` | `any`       | `false`  | Additional custom error data that you supply                                                                                                                                                                           |         |
| `object`       | `Throwable` | `false`  | <p>An instance of an exception object. If there is no message provided, this object will be thrown directly. If there is a message, a<br>CustomException will be thrown and this object will be used as the cause.</p> |         |

## Examples

### Throw a custom exception

Raises a developer-defined exception that can be caught by a try/catch block.

```java
<bx:throw type="ValidationException" message="Email is required">

```

### Throw with detail and error code

```java
<bx:throw
    type="DatabaseError"
    message="Failed to save record"
    detail="Constraint violation on users.email column"
    errorCode="DB_001"
>

```

### Throw with extended info

```java
<bx:throw
    type="AuthException"
    message="Invalid token"
    extendedInfo="#{ userId: 42, token: 'abc123' }#"
>

```

### Rethrow an existing exception object

```java
try {
    riskyOperation();
} catch ( any e ) {
    <bx:throw object="#e#" message="Wrapped: #e.message#">
}

```


---

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