Java: Serializing Array of own Objects

public class Message implements Serializable{

static final long serialVersionUID = -1L;

private String receiver;  //Empfänger
private String sender;  //Absender
private String Betreff;
private String content;
private String timestamp;

static final long serialVersionUID = -1L;

private String receiver;  //Empfänger
private String sender;  //Absender
private String Betreff;
private String content;
private String timestamp;

public static void storeMail(Message[] mail){
    	String filename = "mail.ser";
    	FileOutputStream fos = null;
    	ObjectOutputStream out = null;
    	try {
    		fos = new FileOutputStream(filename);
    		out = new ObjectOutputStream(fos);
    		for (int i=0;i 	Message email1 = new Message("user1", "user2", "Test", "Hallo Test :-) ");
	Message email2 = new Message("user12", "user2", "Test2", "Woohoo");
	Message email3 = new Message("user1", "user2", "Test2", "Okay =) ");
	Message [] mails = {email1, email2, email3};

	Message [] restored = new Message[3];


	storeMail(mails);
	System.out.println("Emailbetreff: "+ email1.getBetreff() + " Inhalt: " + email1.getContent() + ". Safed to file.");

	getStoredMails(restored);   //ERROR
	System.out.println("Emailbetreff: "+ restored[0].getBetreff() + " Inhalt: " + restored[0].getContent() + ". LOADED!");

}