Simple Code

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

public class StudentRecord extends JFrame implements ActionListener{
    private JLabel lbl1 = new JLabel("Full Name: ");
    private JTextField txt1 = new JTextField();
    private JLabel lbl2 = new JLabel("Address: ");
    private JTextField txt2 = new JTextField();
    private JLabel lbl3 = new JLabel("Contact Number: ");
    private JTextField txt3 = new JTextField();
    private JButton btn1 = new JButton("Save Student Record");
    private JButton btn2 = new JButton("Clear All Fields");

public StudentRecord(){
    JFrame f = new JFrame("Student Record by Atom");
    f.setBounds(500,300,300,320);
    f.setLayout(new GridLayout(4,1));
    f.setVisible(true);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JPanel p = new JPanel();
    p.setLayout(new GridLayout(1,1));
    p.add(lbl1);
    p.add(txt1);

    JPanel p2 = new JPanel();
    p2.setLayout(new GridLayout(1,1));
    p2.add(lbl2);
    p2.add(txt2);

    JPanel p3 = new JPanel();
    p3.setLayout(new GridLayout(1,1));
    p3.add(lbl3);
    p3.add(txt3);

    JPanel p4 = new JPanel();
    p4.setLayout(new GridLayout(1,1));
    p4.add(btn1);
    p4.add(btn2);
    btn1.addActionListener(this);
    btn2.addActionListener(this);

        f.add(p);
        f.add(p2);
        f.add(p3);
        f.add(p4);
}
public void AddRecord(){
    try{
        FileWriter fw = new FileWriter("StudentRecords.txt");
        BufferedWriter bw = new BufferedWriter(fw);

        bw.write("Full Name: "+ txt1.getText());
        bw.newLine();
        bw.write("Address: "+ txt2.getText());
        bw.newLine();
        bw.write("Contact Number: "+ txt3.getText());
        bw.newLine();
        bw.close();

        JOptionPane.showMessageDialog(null,"New Student Record Inserted:"+ txt1.getText());

    }catch(Exception e){

    }
}
public void actionPerformed(ActionEvent e){
    Object src = e.getSource();
    String t1 = txt1.getText();
    String t2 = txt2.getText();
    String t3 = txt3.getText();

    if(src == btn1){
        if(t1.trim().isEmpty() || t2.trim().isEmpty() || t3.trim().isEmpty()){
            JOptionPane.showMessageDialog(null,"Cannot display with incomplete data. Please Try again!");
        }else{
            AddRecord();
        }
    }else if (src == btn2){
        txt1.setText("");
        txt2.setText("");
        txt3.setText("");
    }
}
public static void main(String[] args){
    StudentRecord sr = new StudentRecord();
}
}