Can Built-In Exceptions Be Thrown?

Question

In Creating Custom Exceptions, the documentation still claims:

Since you can’t throw built-in Apex exceptions but can only catch them, you can create custom exceptions to throw in your methods.

Is it still true that built-in Exception types cannot be thrown?

Answer 1

As far as I know, @mattandneil was the first to discover this change in this answer to a question by @DanielBallinger.

Despite the documentation's claims to the contrary, the compiler now allows built-in Exception types to be constructed. I confirmed through Execute Anonymous with the following snippet:

try
{
    CalloutException e = new CalloutException();
    e.setMessage('This is a constructed exception!');
    throw e;
}
catch (Exception pokemon)
{ // gotta catch em all!
    system.debug(pokemon);
}

I went through the whole list and what do you know? The following types can all be constructed and thrown:

• AsyncException
• CalloutException
• DmlException
• EmailException
• ExternalObjectException
• InvalidParameterValueException
• LimitException (though it still can't be caught)
• JSONException
• ListException
• MathException
• NoAccessException
• NoDataFoundException
• NoSuchElementException
• NullPointerException
• QueryException
• RequiredFeatureMissingException
• SearchException
• SecurityException
• SerializationException
• SObjectException
• StringException
• TypeException
• VisualforceException
• XmlException

I must admit it feels weird that you can throw new LimitException(). I submitted Feedback on the linked documentation requesting that they update their content.