jos.putNextEntry(new ZipEntry("jar.xml"));
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(jos));
writer.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
writer.newLine();
writer.write("<persistence xmlns=\"http://java.sun.com/xml/ns/persistence\"");
writer.newLine();
writer.write("xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"");
writer.newLine();
writer.write("xsi:schemaLocation=\"http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd\"");