code: public static <T> String marshal(final JAXBContext ctx, final T data) {
          return marshal(ctx, data, null);
      }
docs: Marshals the given data using a given context. A <code>null</code> data argument returns <code>null</code>.
  
  @param ctx
  Context to use - Cannot be <code>null</code>.
  @param data
  Data to serialize or <code>null</code>.
  
  @return XML data or <code>null</code>.
  
  @param <T>
  Type of the data.