Java Object serialization/deserialization

SerializeTest.java

import java.io.*;
import java.util.*;

public class SerializeTest
{

    private static void serialize()
    {
        Map<String, List<String>> headers = new HashMap<String, List<String>>();

        List<String> val1 = new ArrayList<String>();
        val1.add("val1");
        headers.put("key1", val1);

        List<String> val2 = new ArrayList<String>();
        val2.add("val2");
        headers.put("key2", val2);

        List<String> val3 = new ArrayList<String>();
        val3.add("val3");
        headers.put("key3", val3);

        try {
            FileOutputStream fout = new FileOutputStream("test.headers");
            ObjectOutputStream oout = new ObjectOutputStream(fout);
            oout.writeObject(headers);
            oout.close();
            fout.close();
        } catch (IOException e) {
            System.err.println(e.getMessage());
        }
    }

    private static void deserialize()
    {
        Map<String, List<String>> headers = null;

        try {
            FileInputStream fin = new FileInputStream("test.headers");
            ObjectInputStream oin = new ObjectInputStream(fin);
            headers = (Map<String, List<String>>)oin.readObject();
            oin.close();
            fin.close();
        } catch (IOException e) {
            System.err.println(e.getMessage());
        } catch (ClassNotFoundException e) {
            System.err.println(e.getMessage());
        }

        for (String key : headers.keySet()) {
            List<String> val = headers.get(key);
            System.out.println(key + ":" + val.get(0));
        }
    }

    public static void main(String[] args)
    {
        serialize();
        deserialize();
    }
}