import java.io.File;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
public class Main {
public static void main(String[] argv) throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating(true);
factory.setExpandEntityReferences(false);
Document doc = factory.newDocumentBuilder().parse(new File("filename"));
Element element = (Element) doc.getElementsByTagName("b").item(0);
Node parent = element.getParentNode();
parent.removeChild(element);
parent.normalize();
}
}