GridBagLayout not working correctly

I worked with absolute positioning (setBounds and null layout) and now started practicing layout managers, this code is with gridbag layout, but few components are not being displayed, either there is some problem with the cells or something else please help !

import java.util.StringTokenizer;
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
class Calculator extends JFrame
{
    JButton add,sub,mul,div,sin,cos,tan,clear,negate,inverse,zero,one,two,three,four,five,six,seven,eight,nine,equalTo,percentage,sqrt;
    JTextField input;
    GridBagLayout gbl;
    private void addComponent(Component component,int gridx, int gridy, int gridwidth, int gridheight,Insets insets)
    {
        add(component, new GridBagConstraints(gridx, gridy,gridwidth, gridheight, 1.0, 1.0, GridBagConstraints.CENTER, GridBagConstraints.BOTH, insets, 0,0));
    }
    Calculator()
    {
        //setSize(500,400);
        setVisible(true);
        setLayout(gbl=new GridBagLayout());
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        add= new JButton("+");
        sub= new JButton("-");
        mul= new JButton("*");
        div= new JButton("/");
        sin= new JButton("sin");
        cos= new JButton("cos");
        tan= new JButton("tan");
        clear= new JButton("C");
        negate= new JButton("neg");
        inverse= new JButton("1/x");
        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");
        equalTo= new JButton("=");
        percentage= new JButton("%");
        sqrt= new JButton("sqrt");
        input = new JTextField(20);

        addComponent(input,0,0,0,1,new Insets(10,10,100,4)); //tldr

        addComponent(add,0,1,1,1,new Insets(4,4,4,4));
        addComponent(sub,1,1,2,1,new Insets(4,4,4,4));
        addComponent(mul,2,1,3,1,new Insets(4,4,4,4)); // this is not displayed
        addComponent(div,3,1,4,1,new Insets(4,4,4,4));

        addComponent(sin,0,2,1,2,new Insets(4,4,4,4));
        addComponent(cos,1,2,2,2,new Insets(4,4,4,4));
        addComponent(tan,2,2,3,2,new Insets(4,4,4,4)); // this is not displayed
        addComponent(clear,3,2,4,2,new Insets(4,4,4,4));

        addComponent(negate,0,3,1,3,new Insets(4,4,4,4)); // these 4 are not visible
        addComponent(inverse,1,3,2,3,new Insets(4,4,4,4));
        addComponent(zero,2,3,3,3,new Insets(4,4,4,4));
        addComponent(one,3,3,4,3,new Insets(4,4,4,4));
        pack();
    }
    public static void main(String...args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new Calculator();
            }
        });
    }
}

Solution

First off, well done for having a go at using layouts!

The thing that jumps out at me immediately is the values are passing to gridwidth and gridheight

addComponent(add,0,1,1,1,new Insets(4,4,4,4));
addComponent(sub,1,1,2,1,new Insets(4,4,4,4));
addComponent(mul,2,1,3,1,new Insets(4,4,4,4)); // this is not displayed
addComponent(div,3,1,4,1,new Insets(4,4,4,4));

Basically this is saying, add add to grid x/y position 0x1, with a gridwidth/gridheight of 1x1, good so far.

Then add sub at x/y position 1x1 with a gridwidth/gridheight of 1x2, okay...

Then add mul at x/y position 2x1 with a gridwidth/gridheight of 1x3, now we start running into problems...Basically, sub is actually expending into our cell, covering part of us up!

gridwidth and gridheight allow you to define how many cells the component will expand into, most of the time, you want this to be 1x1

Once I corrected all the gridwidth and gridheight values to 1x1, I was able to get this

enter image description here

import java.awt.Component;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

class Calculator extends JFrame {

    JButton add, sub, mul, div, sin, cos, tan, clear, negate, inverse, zero, one, two, three, four, five, six, seven, eight, nine, equalTo, percentage, sqrt;
    JTextField input;
    GridBagLayout gbl;

    private void addComponent(Component component, int gridx, int gridy, int gridwidth, int gridheight, Insets insets) {
        add(component, new GridBagConstraints(gridx, gridy, gridwidth, gridheight, 1.0, 1.0, GridBagConstraints.CENTER, GridBagConstraints.BOTH, insets, 0, 0));
    }

    Calculator() {
        //setSize(500,400);
        setLayout(gbl = new GridBagLayout());
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        add = new JButton("+");
        sub = new JButton("-");
        mul = new JButton("*");
        div = new JButton("/");
        sin = new JButton("sin");
        cos = new JButton("cos");
        tan = new JButton("tan");
        clear = new JButton("C");
        negate = new JButton("neg");
        inverse = new JButton("1/x");
        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");
        equalTo = new JButton("=");
        percentage = new JButton("%");
        sqrt = new JButton("sqrt");
        input = new JTextField(20);

        addComponent(input, 0, 0, 0, 1, new Insets(10, 10, 100, 4)); //tldr

        addComponent(add, 0, 1, 1, 1, new Insets(4, 4, 4, 4));
        addComponent(sub, 1, 1, 1, 1, new Insets(4, 4, 4, 4));
        addComponent(mul, 2, 1, 1, 1, new Insets(4, 4, 4, 4)); // this is not displayed
        addComponent(div, 3, 1, 1, 1, new Insets(4, 4, 4, 4));

        addComponent(sin, 0, 2, 1, 1, new Insets(4, 4, 4, 4));
        addComponent(cos, 1, 2, 1, 1, new Insets(4, 4, 4, 4));
        addComponent(tan, 2, 2, 1, 1, new Insets(4, 4, 4, 4)); // this is not displayed
        addComponent(clear, 3, 2, 1, 1, new Insets(4, 4, 4, 4));

        addComponent(negate, 0, 3, 1, 1, new Insets(4, 4, 4, 4)); // these 4 are not visible
        addComponent(inverse, 1, 3, 1, 1, new Insets(4, 4, 4, 4));
        addComponent(zero, 2, 3, 1, 1, new Insets(4, 4, 4, 4));
        addComponent(one, 3, 3, 1, 1, new Insets(4, 4, 4, 4));
        pack();
        setVisible(true);
    }

    public static void main(String... args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new Calculator();
            }

        });
    }

}