import java.sql.*;
  import java.io.File;
 public class Filewalk {
 int i=0;
 static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";   
 static final String DB_URL = "jdbc:mysql://localhost/STUDENTS"; 
  static final String USER = "root"; 
 static final String PASS = "";

 Connection conn = null; 
 Statement stmt = null;
  //STEP 2: Register JDBC driver 
  Class.forName("com.mysql.jdbc.Driver"); 

  //STEP 3: Open a connection 
  System.out.println("Connecting to a selected database..."); 
  conn = DriverManager.getConnection(DB_URL, USER, PASS); 
  System.out.println("Connected database successfully..."); 

  //STEP 4: Execute a query 
  System.out.println("Creating table in given database..."); 
  stmt = conn.createStatement(); 

  String sq = "CREATE DATABASE FILESS"; 
  stmt.executeUpdate(sq); 

  String sql1 = "CREATE TABLE SYSTEM1 " + 
               "(id INTEGER not NULL, " + 
               " name VARCHAR(255), " +  
               " path VARCHAR(255), " +  
               " size INTEGER, " +  
               " PRIMARY KEY ( id ))";  
  stmt.executeUpdate(sql1); 


  public void walk( String path ) {
  File root = new File( path );
  File[] list = root.listFiles();
 if (list == null) return;
 for ( File f : list ) {
 if ( f.isDirectory() ) {
  walk( f.getAbsolutePath() );
 }
 else {
 String sql2 = "INSERT INTO SYSTEM1" + 
 "VALUES (i++,f.getName(), f.getAbsoluteFile().toString(),f.length())"; 
 stmt.executeUpdate(sql2);
}
}

try{ 
     if(stmt!=null) 
        conn.close(); 
  }catch(SQLException se){ 
  }// do nothing 
  try{ 
     if(conn!=null) 
        conn.close(); 
  }catch(SQLException se){ 
     se.printStackTrace(); 
  }//end finally try
     }//end try 
 System.out.println("Goodbye!"); 
}//end main 


}
public static void main(String[] args) {
Filewalk fw = new Filewalk();
File [] disks = File.listRoots();
for ( File d : disks )
fw.walk(d.toString());
}
}

import java.util.Vector;
import java.io.File;
    public class Filewalker {
        class Item {
        long length;
        String name;
        String path;
        Item (long length1, String name1, String path1)
        {
        length=length;
        name=name1;
        path=path1;
        System.out.println( "File:" + length + " " + name+ "  " + path);
         }
                }        
        Vector <Item> listed;               
        public void walk( String path ) {
            File root = new File( path );
            File[] list = root.listFiles();
            if (list == null) return;
            for ( File f : list ) {
                if ( f.isDirectory() ) {
                    walk( f.getAbsolutePath() );
                }
                else {
                Filewalker fn = new Filewalker();
                Filewalker.Item odyn = fn.new Item (f.length(), f.getName(), f.getPath());
                this.listed.add(odyn);
                System.out.println( "File:" + f.length() + " " + f.getName()+ "  " + f.getPath());
                //System.out.println(this.list.size());
                }
            }
        }
        public static void main(String[] args) {
            Filewalker fw = new Filewalker();
            fw.walk("c:\\" );
        }
    }

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Vector;

    class Test1 {  
       public static void main(String args[])throws java.io.IOException {

       //Filewalker fw = new Filewalker();
       //fw.walk("c:\\" );
            
       String FILE_NAME = "D:\\file.ser"; 
      
       ObjectOutputStream out = new ObjectOutputStream(
       new BufferedOutputStream(new FileOutputStream(FILE_NAME)));
       try {
      out.writeObject(Filewalker.listed);
    } finally {
      out.close();
    }    
       }  
    }  

import java.util.Vector;
import java.io.File;
    public class Filewalker implements java.io.Serializable {
        long length;
        String name;
        String path;
        Filewalker(long length1, String name1, String path1)
        {
        length=length1;
        name=name1;
        path=path1;
        System.out.println( "File:" + length + " " + name+ "  " + path);
         }        
        static Vector <Filewalker> listed = new Vector <Filewalker> ();               
        public static void walk( String path ) {
            File root = new File( path );
            File[] list = root.listFiles();
            if (list == null) return;
            for ( File f : list ) {
                if ( f.isDirectory() ) {
                    walk( f.getAbsolutePath() );
                }
                else {
                
                Filewalker odyn = new Filewalker (f.length(), f.getName(), f.getPath());
                listed.add(odyn);
                System.out.println( "File:" + f.length() + " " + f.getName()+ "  " + f.getPath());
                System.out.println(listed.size());
                }
            }
        }
        public static void main(String[] args) {
            Filewalker.walk("c:\\" );
        }
    }

Exception in thread "main" javax.xml.bind.MarshalException
 - with linked exception:
[com.sun.istack.internal.SAXException2: unable to marshal type "java.util.Vector" as an element because it is missing an @XmlRootElement annotation]

import java.util.Vector;
import java.io.FileOutputStream;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.annotation.XmlRootElement;

public class JavaToXMLDemo {
  public static void main(String[] args) throws Exception {
    Filewalker.walk("c:\\" ); // сам метод ограничил до 100 первых итераций (файлов)
    JAXBContext context = JAXBContext.newInstance(Filewalker.class,Vector.class); //Vector.class --добавил сам ибо его отсутвие вызывало другое исключение, хотя вышеприведеное тоже связано с венктором
    Marshaller m = context.createMarshaller();
    m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
    //Employee object = new Employee();
    //object.setCode("CA");
    //object.setName("Cath");
    //object.setSalary(300);

    m.marshal(Filewalker.listed, System.out); 

  }
}

//@XmlRootElement

/*class Employee {
  private String code;

  private String name;

  private int salary;

  public String getCode() {
    return code;
  }

  public void setCode(String code) {
    this.code = code;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public int getSalary() {
    return salary;
  }

  public void setSalary(int population) {
    this.salary = population;
  }
}
*/

import java.io.File; 
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import java.util.Vector;

public class CrunchifyCreateXMLDOM1 {
 
    public static void xmlmain() {
        DocumentBuilderFactory icFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder icBuilder;
        try {
            icBuilder = icFactory.newDocumentBuilder();
            Document doc = icBuilder.newDocument();
            Element mainRootElement = doc.createElementNS("http://crunchify.com/CrunchifyCreateXMLDOM", "Companies");
            doc.appendChild(mainRootElement);
            
            Filewalker.walk("c:\\" );
            
            for ( Vector <Filewalker> fp : (Vector <Filewalker>)Filewalker.listed ) {
//for ( Vector <Filewalker> fp : Filewalker.listed ) -- таже ошибка error: incompatible types
            
           // append child elements to root element
            mainRootElement.appendChild(getCompany(doc, fp.name, fp.size, fp.path));
           //mainRootElement.appendChild(getCompany(doc, "2", "eBay", "Shopping", "2000"));
           //mainRootElement.appendChild(getCompany(doc, "3", "Google", "Search", "3000"));
 
           // output DOM XML to console 
            Transformer transformer = TransformerFactory.newInstance().newTransformer();
            transformer.setOutputProperty(OutputKeys.INDENT, "yes"); 
            DOMSource source = new DOMSource(doc);
            StreamResult console = new StreamResult(System.out);
            transformer.transform(source, console);}
 
            System.out.println("\nXML DOM Created Successfully..");
 
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
    private static Node getCompany(Document doc, String name, long size, String path) {
        Element company = doc.createElement("File");
        company.appendChild(getCompanyElements(doc, company, "Name", name));
        company.appendChild(getCompanyElements(doc, company, "Size", (String)size)); 
//error: inconvertible types в (String)size)
        company.appendChild(getCompanyElements(doc, company, "Path", path));
        return company;
    }
 
    // utility method to create text node
    private static Node getCompanyElements(Document doc, Element element, String name, String value) {
        Element node = doc.createElement(name);
        node.appendChild(doc.createTextNode(value));
        return node;
    }
    
    public static void main(String[] args) {
		CrunchifyCreateXMLDOM1.xmlmain();
	}
}