ClassCast exception? Hvad gør jeg galt

package student;

public class TAStudent extends Student {

    private String[] TAClasses;

    public TAStudent(String name, String group, String gender, int profeciencyInJava, int cprNumber, String[] TAClasses) {
        super(name, group, gender, profeciencyInJava, cprNumber);
        this.TAClasses = TAClasses;
    }
   
    public String[] getClasses(){
        return TAClasses;
    }
   
    public void setTAClasses(String[] TAClasses){
        this.TAClasses = TAClasses;
    }
   
    void display(){
        System.out.println("I am a TA");
    }
}


ta = (TAStudent) student;
ta.display();