The method createStringFromDOMNode(Node node, boolean omitDeclaration) in XMLUtil doesn't work well.
In the first loading of the transformer, if omitDeclaration is true, the string result doesn't contains xml declaration (expected behaviour). At the second call of the method, string result contains xml declaration (non expected behaviour).
At each transformer.reset() call, the properties of the transformer are reset.
So, the three following Transformers methods are useless:
public final static Transformer getXmlWithDeclarationTransformer()
public final static Transformer getXmlWithoutDeclarationTransformer()
public final static Transformer getWithoutDeclarationTransformer()