DigiDoc4J tries to parse any binary file that added to container as XML

[cbxp]

Resulting in the following logs in system error every time:
[Fatal Error] :1:1: Content is not allowed in prolog.

This message is written by Xerces (included in the JDK), as a result of the following code in DomUtils:

	public static boolean isDOM(final byte[] bytes) {
		try {
			final Document dom = buildDOM(bytes);
			return dom != null;
		} catch (DSSException e) {
			// NOT DOM
			return false;
		}
	}

The question is, why do you try to parse application/pdf binary content as XML?
If you still do, then please ensure no misleading errors are printed that people need to investigate...