import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class MyProg {
    public static void main(String[] args) {
        mainFrame frame = new mainFrame("the database");
    }
}

class mainFrame extends JFrame {
    public mainFrame(String s) {
        super(s);
        setSize(300, 300);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        MyPanel panel = new MyPanel();
        add(panel);
        setVisible(true);
    }
}

class MyPanel extends JPanel {
    public MyPanel(){
        JButton butStudent = new JButton("Student data");
        JButton butFaculty = new JButton("Faculty data");
        JButton butPrint = new JButton("Print the list");
        add(butStudent);
        add(butFaculty);
        add(butPrint);
        ActionListener myListener = new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                String buttonLabel = e.getActionCommand();
                if ((buttonLabel == "Student data") | (buttonLabel == "Faculty data"))
                    makeDataFrame(buttonLabel);
                if (buttonLabel == "Print the list")
                    printList();
            }
        };
        butStudent.addActionListener(myListener);
        butFaculty.addActionListener(myListener);
        butPrint.addActionListener(myListener);
    }

    private void makeDataFrame(String viewFrame) {
        Frame myDataFrame = new DataFrame(viewFrame);
    }

    private void printList() {
        People[] peopleList = DataFrame.getPeople();
        for (int i = 0; i < 10; i++){
            peopleList[i].print();
        }
    };
}

class DataFrame extends JFrame {

    static People[] myPeople = new People[10];
    static int nextIndex = 0;
    final String peopleLabel;
    JTextField nameField;
    JTextField ageField;
    JTextField degreeField;

    public DataFrame(String label){

        peopleLabel = label;

        JPanel buttonPan = new JPanel();
        JPanel fieldPan = new JPanel();
        JLabel nameLabel = new JLabel("Name:");
        nameField = new JTextField(10);
        ageField = new JTextField(10);
        degreeField = new JTextField(10);

        fieldPan.add(nameLabel);
        fieldPan.add(nameField);
        if (peopleLabel == "Student data") {
            JLabel ageLabel = new JLabel("Age:");
            fieldPan.add(ageLabel);
            fieldPan.add(ageField);
        }
        if (peopleLabel == "Faculty data") {
            JLabel degreeLabel = new JLabel("Degree:");
            fieldPan.add(degreeLabel);
            fieldPan.add(degreeField);
        }


        ActionListener myListener = new ActionListener()
        {
            public void actionPerformed(ActionEvent e){
                String labelBut = e.getActionCommand();
                if ((labelBut == "Accept") & (peopleLabel == "Student data"))
                    addStudent();
                if ((labelBut == "Accept") & (peopleLabel == "Faculty data"))
                    addFaculty();
                if (labelBut == "Clear")
                    clear();
                if (labelBut == "Close")
                    close();
            }
        };
        JButton acceptBut = new JButton("Accept");
        JButton clearBut = new JButton("Clear");
        JButton closeBut = new JButton("Close");
        acceptBut.addActionListener(myListener);
        clearBut.addActionListener(myListener);
        closeBut.addActionListener(myListener);
        buttonPan.add(acceptBut);
        buttonPan.add(clearBut);
        buttonPan.add(closeBut);
        setLayout(new GridLayout(2, 1));
        add(fieldPan);
        add(buttonPan);
        setSize(400, 200);
        setVisible(true);
    }

    void addStudent() {
        if (nextIndex > 9) {
            System.out.println("Array is full");
            return;
        }
        myPeople[nextIndex] = new Student(nameField.getText(), Integer.parseInt(ageField.getText()));
        nextIndex++;
    }

    void addFaculty() {
        if (nextIndex > 9) {
            System.out.println("Array is full");
            return;
        }
        myPeople[nextIndex] = new Faculty(nameField.getText(), degreeField.getText());
        nextIndex++;
    }

    void clear() {
        nameField.setText("");
        if (peopleLabel == "Student data")
            ageField.setText("");
        if (peopleLabel == "Faculty data")
            degreeField.setText("");
    }

    void close() {
        this.dispose();
    }
    public static People[] getPeople() {
        return myPeople;
    };
}

abstract class People {
    String name;
    public People(String name){
        this.name = name;
    };
    abstract void print();
}

class Student extends People {
    int age;
    public Student(String name, int age) {
        super(name);
        this.age = age;
    };
    void print() {
        System.out.println("Student " + name + ", " + age + " years");
    }
}

class Faculty extends People {
    String degree;
    public Faculty(String name, String degree) {
        super(name);
        this.degree = degree;
    };
    void print() {
        System.out.println("Faculty " + name + ", " + degree+ " degree");
    }
}

Спасибо.

void clear() {
        nameField.setText("");
        if (peopleLabel == "Student data")
            ageField.setText("");
        if (peopleLabel == "Faculty data")
            degreeField.setText("");