version 1

CalculatorGUI.java

+package com.company;
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.awt.event.KeyEvent;
+import java.awt.event.KeyListener;
+
+public class CalculatorGUI implements ActionListener, KeyListener {
+    JFrame calcFrame;
+
+
+    public JTextArea display;
+
+    protected int a, b, cs;
+
+    public CalculatorGUI(){
+        calcFrame = new JFrame();
+        calcFrame.setTitle("AUT Calculator");
+        calcFrame.setSize(350, 370);
+        calcFrame.setLocation(100, 200);
+
+
+        JMenuBar menuBar = new JMenuBar();
+        JMenu fileMenu = new JMenu("File");
+        fileMenu.setMnemonic('F');
+        JMenuItem exitItem = new JMenuItem("Exit"); // create exit item
+        exitItem.setMnemonic('x');
+        exitItem.addActionListener(new ActionListener() {
+            public void actionPerformed(ActionEvent ev) {
+                System.exit(0);
+            }
+        });
+        fileMenu.add(exitItem);
+        menuBar.add(fileMenu);
+        //calcFrame.add(menuBar);
+
+
+        JPanel keyboardPanel = new JPanel();
+        keyboardPanel.setLayout(new GridLayout(5,3));
+
+
+        display = new JTextArea(3 , 10);
+        display.setEditable(false);
+        display.setToolTipText("for displaying");
+        display.setFont(new Font("Arial", 14, 14));
+        display.setBackground(Color.GREEN);
+
+        for(int i = 9 ; i > 0 ; i--)
+        {
+            JButton btn = new JButton();
+            btn.setText(""+i);
+            btn.setToolTipText("number " + i);
+            btn.setFocusable(true);
+            btn.addActionListener(this);
+            btn.addKeyListener(this);
+            keyboardPanel.add(btn);
+        }
+        JButton sumBtn = new JButton();
+        sumBtn.setText("+");
+        sumBtn.setToolTipText("btn +");
+        sumBtn.setFocusable(true);
+        sumBtn.addKeyListener(this);
+        sumBtn.addActionListener(this);
+        keyboardPanel.add(sumBtn);
+
+        JButton zeroBtn = new JButton();
+        zeroBtn.setText("0");
+        zeroBtn.setToolTipText("number 0");
+        zeroBtn.setFocusable(true);
+        zeroBtn.addKeyListener(this);
+        zeroBtn.addActionListener(this);
+        keyboardPanel.add(zeroBtn);
+
+        JButton doBtn = new JButton();
+        doBtn.setText("=");
+        doBtn.setToolTipText("btn =");
+        doBtn.setFocusable(true);
+        doBtn.addKeyListener(this);
+        doBtn.addActionListener(this);
+        keyboardPanel.add(doBtn);
+
+        JButton mulBtn = new JButton();
+        mulBtn.setText("*");
+        mulBtn.setToolTipText("btn *");
+        mulBtn.setFocusable(true);
+        mulBtn.addKeyListener(this);
+        mulBtn.addActionListener(this);
+        keyboardPanel.add(mulBtn);
+
+        JButton divideBtn = new JButton();
+        divideBtn.setText("/");
+        divideBtn.setToolTipText("btn /");
+        divideBtn.setFocusable(true);
+        divideBtn.addKeyListener(this);
+        divideBtn.addActionListener(this);
+        keyboardPanel.add(divideBtn);
+
+        JButton subBtn = new JButton();
+        subBtn.setText("-");
+        subBtn.setToolTipText("btn -");
+        subBtn.addActionListener(this);
+        keyboardPanel.add(subBtn);
+
+        JPanel totalOne = new JPanel();
+        totalOne.setSize(350, 370);
+        totalOne.setLayout(new GridLayout(2,1));
+        totalOne.add(display);
+        totalOne.add(keyboardPanel);
+        JTabbedPane tp = new JTabbedPane();
+        totalOne.addKeyListener(this);
+        tp.add("manual", totalOne);
+        tp.addKeyListener(this);
+
+        //--------------------------------------------------------------
+
+
+        JPanel keyboardPanel2 = new JPanel();
+        keyboardPanel2.setLayout(new GridLayout(6,3));
+
+        for(int i = 9 ; i > 0 ; i--)
+        {
+            JButton btn = new JButton();
+            btn.setText(""+i);
+            keyboardPanel2.add(btn);
+        }
+        JButton sumBtn2 = new JButton();
+        sumBtn2.setText("+");
+        keyboardPanel2.add(sumBtn2);
+
+        JButton zeroBtn2 = new JButton();
+        zeroBtn2.setText("0");
+        keyboardPanel2.add(zeroBtn2);
+
+        JButton doBtn2 = new JButton();
+        doBtn2.setText("=");
+        keyboardPanel2.add(doBtn2);
+
+        JButton mulBtn2 = new JButton();
+        mulBtn2.setText("*");
+        keyboardPanel2.add(mulBtn2);
+
+        JButton divideBtn2 = new JButton();
+        divideBtn2.setText("=");
+        keyboardPanel2.add(divideBtn2);
+
+        JButton subBtn2 = new JButton();
+        subBtn2.setText("-");
+        keyboardPanel2.add(subBtn2);
+
+        JButton sinBtn = new JButton();
+        sinBtn.setText("sin / cos");
+        keyboardPanel2.add(sinBtn);
+
+        JButton tanBtn = new JButton();
+        tanBtn.setText("tan / cot");
+        keyboardPanel2.add(tanBtn);
+
+        JButton logBtn = new JButton();
+        logBtn.setText("log / exp");
+        keyboardPanel2.add(logBtn);
+
+        JTextArea display2 = new JTextArea(3 , 10);
+        display2.setEditable(false);
+        display2.setFont(new Font("Arial", 14, 14));
+        display2.setBackground(Color.GREEN);
+
+        JButton shBtn = new JButton("Shift");
+        shBtn.setBackground(Color.RED);
+
+        JPanel totalTwo = new JPanel();
+        totalTwo.setLayout(new GridLayout(3,1));
+        totalTwo.add(display2);
+        totalTwo.add(keyboardPanel2);
+        totalTwo.add(shBtn);
+        tp.add("engenering", totalTwo);
+
+
+        calcFrame.add(menuBar, BorderLayout.NORTH);
+        calcFrame.add(tp, BorderLayout.CENTER);
+        //calcFrame.setLayout(null);
+        calcFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        calcFrame.setVisible(true);
+    }
+
+    @Override
+    public void actionPerformed(ActionEvent e) {
+        JButton btn = (JButton) e.getSource();
+        String s = btn.getText();
+        if(s != "+" && s != "-" && s != "/" && s != "=" && s != "*")
+        {
+            display.setText(display.getText() + s);
+        }
+
+        switch(s){
+            case "+":
+                a = Integer.parseInt(display.getText());
+                display.setText("");
+                cs = 1;
+                break;
+            case "-":
+                a = Integer.parseInt(display.getText());
+                display.setText("");
+                cs = 2;
+                break;
+            case "/":
+                a = Integer.parseInt(display.getText());
+                display.setText("");
+                cs = 3;
+                break;
+            case "*":
+                a = Integer.parseInt(display.getText());
+                display.setText("");
+                cs = 4;
+                break;
+            case "=":
+                b = Integer.parseInt(display.getText());
+                if(cs == 1)
+                    display.setText("" + (a + b));
+                else if(cs == 2)
+                    display.setText("" + (a - b));
+                else if (cs == 3)
+                    display.setText("" + (a / b));
+                else if (cs == 4)
+                    display.setText("" + (a * b));
+                break;
+        }
+
+    }
+
+    @Override
+    public void keyTyped(KeyEvent e) {
+    }
+
+    @Override
+    public void keyPressed(KeyEvent e) {
+    }
+
+    @Override
+    public void keyReleased(KeyEvent e) {
+
+        int kRealeased = e.getKeyCode();
+        switch (kRealeased){
+            case KeyEvent.VK_NUMPAD1:
+                display.setText(display.getText()+"1");
+                break;
+            case KeyEvent.VK_NUMPAD2:
+                display.setText(display.getText()+"2");
+                break;
+            case KeyEvent.VK_NUMPAD3:
+                display.setText(display.getText()+"3");
+                break;
+            case KeyEvent.VK_NUMPAD4:
+                display.setText(display.getText()+"4");
+                break;
+            case KeyEvent.VK_NUMPAD5:
+                display.setText(display.getText()+"5");
+                break;
+            case KeyEvent.VK_NUMPAD6:
+                display.setText(display.getText()+"6");
+                break;
+            case KeyEvent.VK_NUMPAD7:
+                display.setText(display.getText()+"7");
+                break;
+            case KeyEvent.VK_NUMPAD8:
+                display.setText(display.getText()+"8");
+                break;
+            case KeyEvent.VK_NUMPAD9:
+                display.setText(display.getText()+"9");
+                break;
+            case KeyEvent.VK_NUMPAD0:
+                display.setText(display.getText()+"0");
+                break;
+            case KeyEvent.VK_ADD:
+                a = Integer.parseInt(display.getText());
+                display.setText("");
+                cs = 1;
+                break;
+            case KeyEvent.VK_SUBTRACT:
+                a = Integer.parseInt(display.getText());
+                display.setText("");
+                cs = 2;
+                break;
+            case KeyEvent.VK_DIVIDE:
+                a = Integer.parseInt(display.getText());
+                display.setText("");
+                cs = 3;
+                break;
+            case KeyEvent.VK_MULTIPLY:
+                a = Integer.parseInt(display.getText());
+                display.setText("");
+                cs = 4;
+                break;
+            case KeyEvent.VK_EQUALS:
+                b = Integer.parseInt(display.getText());
+                if(cs == 1)
+                    display.setText("" + (a + b));
+                else if(cs == 2)
+                    display.setText("" + (a - b));
+                else if (cs == 3)
+                    display.setText("" + (a / b));
+                else if (cs == 4)
+                    display.setText("" + (a * b));
+                break;
+
+        }
+    }
+}

Main.java

+package com.company;
+
+public class Main {
+
+    public static void main(String[] args) {
+
+        CalculatorGUI calculator = new CalculatorGUI();
+    }
+}