Creates an XMLObject from an element.

  Creates an XMLObject from an element.
Parameters:
- objElem - an Object element
Throws:
- MarshalException - if there is an error when unmarshalling

  Creates an XMLObject from the specified parameters.

  Creates an XMLObject from the specified parameters.
Returns: an XMLObject
Parameters:
- content - a list of {@link XMLStructure}s. The list is defensively copied to protect against subsequent modification. May be null or empty.
- id - the Id (may be null)
- mimeType - the mime type (may be null)
- encoding - the encoding (may be null)
Throws:
- ClassCastException - if content contains any entries that are not of type {@link XMLStructure}