jodd-mail/src/main/java/jodd/mail/CommonEmail.java
public T attachment(final EmailAttachment<? extends DataSource> attachment) {
		attachment.setContentId(null);
		return storeAttachment(attachment);
	}
public T attachment(final EmailAttachment<? extends DataSource> attachment) {
		attachment.setContentId(null);
		return storeAttachment(attachment);
	}
public T attachment ( final EmailAttachment < ? extends DataSource > attachment ) { attachment . setContentId ( null ) ; return storeAttachment ( attachment ) ; }
Adds {@link EmailAttachment}. Content ID will be set to {@code null}.

@param attachment {@link EmailAttachment} to add.
@return this
Adds { @link EmailAttachment } . Content ID will be set to { @code null } .