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Basic GUI Calculatorcalculator

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I know there's loads of these out there but I thought I'd give it a shot, my mate made a calculator but he used a GUI Builder and I personally prefer typing my GUI's by hand.

I'm basically new? So I've finished my first year of university (moving on to my second year) and I'm studying BSc Artificial Intelligence and Robotics, I wanted to test my Java skills considering I finished like a month ago and wanted to see what I could remember.

I'm uploading the code here, for any advice as I'd like to type Java with the correct rules, regulations or 'good habits'?

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import javax.swing.JFrame;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import javax.swing.ImageIcon;
public class Main extends JFrame
{
 private Interface anInterface = new Interface();
 private ImagePanel imagePanel = new ImagePanel();
 private String request = "";
 public Main()
 {
 imagePanel.add(anInterface);
 add(imagePanel);
 actions();
 pack();
 setVisible(true);
 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 setLocationRelativeTo(null);
 setSize(225, 300);
 setTitle("Calculator");
 setResizable(false);
 }
 public void actions()
 {
 anInterface.calculatorButtons.zero.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += 0;
 anInterface.calculatorScreen.results.setText(text + 0);
 }
 });
 anInterface.calculatorButtons.one.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += 1;
 anInterface.calculatorScreen.results.setText(text + 1);
 }
 });
 anInterface.calculatorButtons.two.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += 2;
 anInterface.calculatorScreen.results.setText(text + 2);
 }
 });
 anInterface.calculatorButtons.three.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += 3;
 anInterface.calculatorScreen.results.setText(text + 3);
 }
 });
 anInterface.calculatorButtons.four.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += 4;
 anInterface.calculatorScreen.results.setText(text + 4);
 }
 });
 anInterface.calculatorButtons.five.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += 5;
 anInterface.calculatorScreen.results.setText(text + 5);
 }
 });
 anInterface.calculatorButtons.six.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += 6;
 anInterface.calculatorScreen.results.setText(text + 6);
 }
 });
 anInterface.calculatorButtons.seven.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += 7;
 anInterface.calculatorScreen.results.setText(text + 7);
 }
 });
 anInterface.calculatorButtons.eight.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += 8;
 anInterface.calculatorScreen.results.setText(text + 8);
 }
 });
 anInterface.calculatorButtons.nine.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += 9;
 anInterface.calculatorScreen.results.setText(text + 9);
 }
 });
 anInterface.calculatorButtons.dot.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += ".";
 anInterface.calculatorScreen.results.setText(text + ".");
 }
 });
 anInterface.calculatorButtons.plus.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += "+";
 anInterface.calculatorScreen.results.setText(text + "+");
 }
 });
 anInterface.calculatorButtons.divide.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += "/";
 anInterface.calculatorScreen.results.setText(text + "÷");
 }
 });
 anInterface.calculatorButtons.multiply.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += "*";
 anInterface.calculatorScreen.results.setText(text + ×ばつ");
 }
 });
 anInterface.calculatorButtons.minus.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 String text = anInterface.calculatorScreen.results.getText();
 request += "-";
 anInterface.calculatorScreen.results.setText(text + "-");
 }
 });
 anInterface.calculatorButtons.ac.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 request = "";
 anInterface.calculatorScreen.results.setText("");
 }
 });
 anInterface.clearButton.equals.addActionListener(new ActionListener()
 {
 @Override
 public void actionPerformed(ActionEvent e)
 {
 try
 {
 ScriptEngineManager mgr = new ScriptEngineManager();
 ScriptEngine engine = mgr.getEngineByName("JavaScript");
 String answer = engine.eval(request).toString();
 anInterface.calculatorScreen.results.setText("" + answer);
 request = answer;
 }
 catch(ScriptException | NullPointerException e1)
 {
 anInterface.calculatorScreen.results.setText("ERROR");
 }
 }
 });
 }
 public static void main(String[] args)
 {
 Main itf = new Main();
 }
}
class CalculatorButtons extends JPanel
{
 protected JButton zero;
 protected JButton one;
 protected JButton two;
 protected JButton three;
 protected JButton four;
 protected JButton five;
 protected JButton six;
 protected JButton seven;
 protected JButton eight;
 protected JButton nine;
 protected JButton dot;
 protected JButton plus;
 protected JButton divide;
 protected JButton multiply;
 protected JButton minus;
 protected JButton ac;
 public CalculatorButtons()
 {
 setOpaque(false);
 setLayout(new GridBagLayout());
 zero = new JButton("0");
 one = new JButton("1");
 two = new JButton("2");
 three = new JButton("3");
 four = new JButton("4");
 five = new JButton("5");
 six = new JButton("6");
 seven = new JButton("7");
 eight = new JButton("8");
 nine = new JButton("9");
 dot = new JButton(".");
 plus = new JButton("+");
 divide = new JButton("÷");
 multiply = new JButton(×ばつ");
 minus = new JButton("-");
 ac = new JButton("AC");
 JLabel space = new JLabel(" ");
 GridBagConstraints gbc = new GridBagConstraints();
 gbc.ipadx = -20;
 gbc.gridx = 0;
 gbc.gridy = 4;
 gbc.anchor = GridBagConstraints.WEST;
 add(zero, gbc);
 gbc.anchor = GridBagConstraints.CENTER;
 add(dot, gbc);
 gbc.anchor = GridBagConstraints.EAST;
 add(ac, gbc);
 gbc.gridx = 0;
 gbc.gridy = 3;
 gbc.anchor = GridBagConstraints.WEST;
 add(one, gbc);
 gbc.anchor = GridBagConstraints.CENTER;
 add(two, gbc);
 gbc.anchor = GridBagConstraints.EAST;
 add(three, gbc);
 gbc.gridx = 0;
 gbc.gridy = 2;
 gbc.anchor = GridBagConstraints.WEST;
 add(four, gbc);
 gbc.anchor = GridBagConstraints.CENTER;
 add(five, gbc);
 gbc.anchor = GridBagConstraints.EAST;
 add(six, gbc);
 gbc.gridx = 0;
 gbc.gridy = 1;
 gbc.anchor = GridBagConstraints.WEST;
 add(seven, gbc);
 gbc.anchor = GridBagConstraints.CENTER;
 add(eight, gbc);
 gbc.anchor = GridBagConstraints.EAST;
 add(nine, gbc);
 gbc.gridx = 1;
 gbc.gridy = 1;
 add(plus, gbc);
 gbc.gridx = 1;
 gbc.gridy = 2;
 add(divide, gbc);
 gbc.gridx = 1;
 gbc.gridy = 3;
 add(multiply, gbc);
 gbc.gridx = 1;
 gbc.gridy = 4;
 add(minus, gbc);
 gbc.gridx = 0;
 gbc.gridy = 5;
 add(space);
 }
}
class CalculatorScreen extends JPanel
{
 protected JTextArea results;
 protected JScrollPane scrollPane;
 public CalculatorScreen()
 {
 setOpaque(false);
 results = new JTextArea(5, 16);
 results.setEditable(false);
 results.setLineWrap(true);
 scrollPane = new JScrollPane(results);
 GridBagConstraints gbc = new GridBagConstraints();
 gbc.gridx = 0;
 gbc.gridy = 0;
 add(scrollPane, gbc);
 }
}
class ClearButton extends JPanel
{
 protected JButton equals;
 public ClearButton()
 {
 setOpaque(false);
 setLayout(new GridBagLayout());
 equals = new JButton("=");
 GridBagConstraints gbc = new GridBagConstraints();
 gbc.gridx = 0;
 gbc.gridy = 0;
 gbc.ipadx = 124;
 add(equals, gbc);
 }
}
class ImagePanel extends JPanel
{
 protected Image loginImage;
 public ImagePanel()
 {
 this.loginImage =
 new ImageIcon(getClass().getResource("Pics/CalcBackground.jpg")).getImage();
 Dimension size = new Dimension(loginImage.getWidth(null), loginImage.getHeight(null));
 setPreferredSize(size);
 setMinimumSize(size);
 setMaximumSize(size);
 setSize(size);
 setLayout(new GridBagLayout());
 }
 protected void paintComponent(Graphics g) {
 g.drawImage(loginImage, 0, 0, null);
 }
}
class Interface extends JPanel
{
 protected CalculatorScreen calculatorScreen = new CalculatorScreen();
 protected CalculatorButtons calculatorButtons = new CalculatorButtons();
 protected ClearButton clearButton = new ClearButton();
 Interface()
 {
 setOpaque(false);
 setLayout(new GridBagLayout());
 GridBagConstraints gbc = new GridBagConstraints();
 gbc.gridx = 0;
 gbc.gridy = 0;
 add(calculatorScreen, gbc);
 gbc.ipady = 0;
 gbc.gridx = 0;
 gbc.gridy = 1;
 add(calculatorButtons, gbc);
 gbc.gridx = 0;
 gbc.gridy = 2;
 add(clearButton, gbc);
 }
}

Image of the Calculator

The link for the background image of the calculator: http://imgur.com/zZehZlX

So, I'm not sure if I'm a beginner? I class my self as a beginner as I have no idea what level of skill you stop being a beginner at. The code itself is in 6 different separate classes, I've been told previously on StackOverflow to submit my code in one file, so that's what I've done here.

I realise that I have a lot of actions for buttons when I could try to limit those and make it more reusable just not sure how.

Any help on improving my style of typing code would be helpful, and I appreciate every bit.

Thanks.