<?xml version="1.0" encoding="UTF-8"?>
<команда>
	<Параметр>Параметр</Параметр>
	<Параметр1>Параметр1</Параметр1>
</команда>

class команда {

private T Параметр пар;
private T Параметр1 пар2;


get()
set()
}

import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.Element;

@XmlRootElement
public class Address {

    private String street;

    private String city;

    private String state;

    private String country;

    @XmlElement(name="postal-code")
    private String postalCode;

}

<address>
    <street>123 A Street</street>
    <city>Any Town</city>
    <state>A State</state>
    <postal-code>12345</postal-code>
</address>

import java.io.FileReader;
import java.io.Writer;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;

public class Utils {
    public static <T> T unmarshaller(Class<T> aClass , FileReader fileReader) throws JAXBException {
       JAXBContext context = JAXBContext.newInstance(aClass);
       Unmarshaller um = context.createUnmarshaller();
       T result = (T) um.unmarshal(fileReader);
       return result;
     
 }
    
    public static <T> void marshaller(T obj, Writer writer) throws JAXBException {
        JAXBContext context = JAXBContext.newInstance(obj.getClass());
        Marshaller m = context.createMarshaller();
        m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
        m.marshal(obj, writer);
    }

   Bookstore bookstore =  Utils.unmarshaller(Bookstore.class, new FileReader(BOOKSTORE_XML));
   list = bookstore .getBooksList();
       
    
        
  Writer writer = new FileWriter("new.xml"); 
  Utils.marshaller(b , writer);

/**
 * Маркерный интерфейс 
 */
interface Entity {
    
}


public class Book implements Entity{
...

public static <T extends Entity> T unmarshaller(Class<T> aClass , Reader reader) throws JAXBException {