Serialization Failure

public class Start {
    public static void main(String[] args) {
        File aFile = new File("");
        String dataPathBIN = aFile.getAbsolutePath() + "/data/wiprofs.dta";
        String dataPathXML = aFile.getAbsolutePath() + "/data/wiprofs.xml";
         System.out.println("Test binaray serialization");
         new BinarySerialization(dataPathBIN);
         System.out.println();
         System.out.println("Test serialization with xml");
         new XMLSerialization(dataPathXML);
    }
}

public class Student implements Serializable{
    private static final long serialVersionUID = 1L;
    private int matrikel = 0;
    private String name = "", eMail = "";

    public Student() {
    }
    public Student(int matrikel, String name, String eMail) {
        this.matrikel = matrikel;
        this.name = name;
        this.eMail = eMail;
    }

    public int getMatrikel() { return matrikel;
    }
    public String geteMail() { return eMail;
    }
    public String getName() { return name;
    }
    public void setMatrikel(int matrikel) { this.matrikel = matrikel;
    }
    public void setName(String name) { this.name = name;
    }
    public void seteMail(String eMail) { this.eMail = eMail;
    }
}

import java.util.ArrayList;


public abstract class Serialization {
    protected ArrayList<Student> students = new ArrayList<Student>();
    protected String dataPath = "";

    public Serialization(String dataPath) {
        this.dataPath = dataPath;
        }
    protected void createData() {
        students.add(new Student(111111, "Peter Petersen", "petersen@stud.de"));
        students.add(new Student(222222, "Chris Chrisson", "chrisson@stud.de"));
        students.add(new Student(333333, "Karla Karlson", "karlson@stud.de"));
        students.add(new Student(444444, "Rocky Balboa", "balboa@stud.de"));
    }

    protected void clearData() {
        students.removeAll(students);
    }
    protected void showData() {
        for(Student student : students) {
            System.out.println(student);
        }
    }

    protected abstract void readData();
    protected abstract void writeData();
}


public class BinarySerialization extends Serialization{

    public BinarySerialization(String dataPath) {
        super(dataPath);
        createData();
        writeData();
        clearData();
        readData();
        showData();
    }
    @SuppressWarnings("unchecked")
    @Override
    protected void readData() {
        try {
            FileInputStream in = new FileInputStream(dataPath);
            ObjectInputStream oin = new ObjectInputStream(in);
            students = (ArrayList<Student>)oin.readObject();
            oin.close();
        } catch (Exception e) {
            System.out.println(e);
        }
    }

    @Override
    protected void writeData() {
        try {
            FileOutputStream out = new FileOutputStream(dataPath);
            ObjectOutputStream oout = new ObjectOutputStream(out);
            oout.writeObject(students);
            oout.close();
        } catch (Exception e) {
            System.out.println(e);
        }
    }
}