How to Create a Table in Java?

Creating a table in Java typically involves using data structures like arrays or collections. There are a few different ways to create a table in Java. One way is to use the JTable class. In this section, we will discuss the various ways to create table in Java.

1. Using a 2D Array

TableCreationGUI.java

import javax.swing.*;
import java.awt.*;
public class TableCreationGUI extends JFrame {
    private JTable table;
    public TableCreationGUI() {
        int rows = 3;
        int columns = 4;
        int[][] tab = new int[rows][columns];
        // Populate the table with values using nested loops
        int t = 0;
        while (t < rows) {
            int q = 0;
            while (q < columns) {
                tab[t][q] = t * columns + q + 1;
                q++;
            }
            t++;
        }
        // Convert data to a 2D array for the table model
        Object[][] dataArray = new Object[rows][columns];
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < columns; j++) {
                dataArray[i][j] = tab[i][j];
            }
        }
        // Create the table model
        table = new JTable(dataArray, new Object[]{"Column 1", "Column 2", "Column 3", "Column 4"});
        // Create and configure the frame
        JFrame frame = new JFrame("Table Creation GUI");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new BorderLayout());
        // Add the table to the frame
        frame.add(new JScrollPane(table), BorderLayout.CENTER);
        // Set frame properties
        frame.setSize(400, 300);
        frame.setLocationRelativeTo(null); // Center the frame
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new TableCreationGUI());
    }
}

Output:

Explanation

Swing is used by the TableCreationGUI class to provide a graphical user interface (GUI) by extending JFrame. The table in this GUI is represented by a JTable component, and the data is given by means of a 2D array. To make sure that the GUI is built on the Event Dispatch Thread (EDT), the programme makes use of the SwingUtilities.invokeLater() method.

To act as the model for the JTable, the data in the 2D array is transformed into an object array (Object[][] dataArray). To enable scrolling in the event that the table content exceeds the frame size, a JScrollPane is also included.

2. Using ArrayList of ArrayList:

TableCreationGUI.java

import javax.swing.*;
import java.awt.*;
import java.util.*;
public class TableCreationGUI extends JFrame {
    private JTable table;
    public TableCreationGUI() {
        int rows = 3;
        int columns = 4;
        // Create an ArrayList to store rows
        ArrayList<ArrayList<Integer>> tableList = new ArrayList<>();
        int i = 0;
        while (i < rows) {
            ArrayList<Integer> row = new ArrayList<>();
            int j = 0;
            while (j < columns) {
                row.add(i * columns + j + 1);
                j++;
            }
            tableList.add(row);
            i++;
        }
        // Convert data to a 2D array for the table model
        Object[][] dataArray = new Object[rows][columns];
        int k = 0;
while (k < rows) {
    	int l = 0;
    	while (l < columns) {
        	dataArray[k][l] = tableList.get(k).get(l);
        	l++;
    	}
    	k++;
}
        // Create the table model
        table = new JTable(dataArray, new Object[]{"Column 1", "Column 2", "Column 3", "Column 4"});
        // Create and configure the frame
        JFrame frame = new JFrame("Table Creation GUI");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new BorderLayout());
        // Add the table to the frame
        frame.add(new JScrollPane(table), BorderLayout.CENTER);
        // Set frame properties
        frame.setSize(400, 300);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new TableCreationGUI());
    }
}

Output:

Explanation

The programme represents the table's rows and columns using an ArrayList<ArrayList<Integer>>. Swing components are used to form the GUI, and the rows and values in the ArrayList of ArrayLists are iterated over using an Iterator. Next, the data is transformed into an object array for the JTable model (Object[][] dataArray). The application offers a dynamic and adaptable framework for making and presenting tables of different sizes.

3. Using Arrays and StringBuilder Class:

TableCreationGUI.java

import javax.swing.*;
import java.awt.*;
public class TableCreationGUI extends JFrame {
    private JTextArea textArea;
    public TableCreationGUI() {
        int rows = 3;
        int columns = 4;
        // Create a StringBuilder to build the table string
        StringBuilder tableString = new StringBuilder();
        // Populate the table string with values using while loops
        int k = 0;
        while (k < rows) {
            int i = 0;
            while (i < columns) {
                tableString.append((k * columns + i + 1) + "\t");
                i++;
            }
            tableString.append("\n");
            k++;
        }
        // Create and configure the frame
        JFrame frame = new JFrame("Table Creation GUI");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new BorderLayout());
        // Add the text area to the frame
        textArea = new JTextArea(tableString.toString());
        frame.add(new JScrollPane(textArea), BorderLayout.CENTER);
        // Set frame properties
        frame.setSize(400, 300);
        frame.setLocationRelativeTo(null); 
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new TableCreationGUI());
    }
}

Output:

Explanation

This program's GUI uses a JTextArea component to display a table inside a scrollable text area. Using nested while loops and a StringBuilder, the table's content is created. The StringBuilder is then used to create the table's string representation. If the table's content is larger than the frame, a JScrollPane is added to enable scrolling. This method offers a straightforward approach to display tables in a graphical user interface text field.

4. Using Java Collections Framework (List of Lists):

TableCreationGUI.java

import javax.swing.*;
import java.awt.*;
import java.util.*;
public class TableCreationGUI extends JFrame {
    private JTable table;
    public TableCreationGUI() {
        int rows = 3;
        int columns = 4;
        List<List<Integer>> tableList = new ArrayList<>();
        // Populate the table with values using while loops
        int k = 0;
        while (k < rows) {
            ArrayList<Integer> row = new ArrayList<>();
            int i = 0;
            while (i < columns) {
                row.add(k * columns + i + 1);
                i++;
            }
            tableList.add(row);
            k++;
        }
        // Convert data to a 2D array for the table model
        Object[][] dataArray = new Object[rows][columns];
int l = 0;
while (l < rows) {
    		int m = 0;
    		while (m < columns) {
        			dataArray[l][m] = tableList.get(l).get(m);
        			m++;
    		}
    	l++;
}
        // Create the table model
        table = new JTable(dataArray, new Object[]{"Column 1", "Column 2", "Column 3", "Column 4"});
        // Create and configure the frame
        JFrame frame = new JFrame("Table Creation GUI");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new BorderLayout());
        // Add the table to the frame
        frame.add(new JScrollPane(table), BorderLayout.CENTER);
        // Set frame properties
        frame.setSize(400, 300);
        frame.setLocationRelativeTo(null); // Center the frame
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new TableCreationGUI());
    }
}

Output:

Explanation

The rows and columns of the table are represented by this programme using a List<List<Integer>> and the Java Collections Framework. Swing components are used to create the GUI, and an Iterator is used to iterate through the values and rows in the List of Lists. For the JTable paradigm, the data is transformed into an object array (Object[][] dataArray), much like in earlier examples. This method offers readability and versatility when making and presenting tables.

5. Using Java Streams

TableCreationGUI.java

import javax.swing.*;
import java.awt.*;
import java.util.stream.IntStream;
public class TableCreationGUI extends JFrame {
    private JTextArea textArea;
    public TableCreationGUI() {
        int rows = 3;
        int columns = 4;
        // Use Java Streams to create and print the table
        StringBuilder tableString = new StringBuilder();
        int i = 0;
        while (i < rows) {
            int j = 0;
            while (j < columns) {
                final int finalI = i;
                final int finalJ = j;
                tableString.append((finalI * columns + finalJ + 1) + "\t");
                j++;
            }
            tableString.append("\n");
            i++;
        }
        // Create and configure the frame
        JFrame frame = new JFrame("Table Creation GUI");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new BorderLayout());
        // Add the text area to the frame
        textArea = new JTextArea(tableString.toString());
        frame.add(new JScrollPane(textArea), BorderLayout.CENTER);
        // Set frame properties
        frame.setSize(400, 300);
        frame.setLocationRelativeTo(null); 
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new TableCreationGUI());
    }
}

Output:

Explanation

Java Streams are used in this programme to expedite the development and printing of the table. Swing components are utilised to generate the GUI, and nested while loops are used to fill the StringBuilder with table information. Next, a scrollable text box with a JTextArea containing the generated string is shown. Using Java Streams makes code more expressive and concise, which improves readability and maintainability.

6. Using String Formatting for a Neat Display

TableCreationGUI.java

import javax.swing.*;
import java.awt.*;
public class TableCreationGUI extends JFrame {
    private JTextArea textArea;
    public TableCreationGUI() {
        long rows = 3;
        long columns = 4;
        // Use String formatting for a neat table display using while loops
        StringBuilder tableString = new StringBuilder();
        long k = 0;
        while (k < rows) {
            long i = 0;
            while (i < columns) {
                tableString.append(String.format("%-5d", k * columns + i + 1));
                i++;
            }
            tableString.append("\n");
            k++;
        }
        // Create and configure the frame
        JFrame frame = new JFrame("Table Creation GUI");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new BorderLayout());
        // Add the text area to the frame
        textArea = new JTextArea(tableString.toString());
        frame.add(new JScrollPane(textArea), BorderLayout.CENTER);
        // Set frame properties
        frame.setSize(400, 300);
        frame.setLocationRelativeTo(null); 
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new TableCreationGUI());
    }
}

Output:

Explanation

This program's GUI makes use of String.format() to produce a tidy table display. As in earlier examples, nested while loops are used to create the table content, and the resultant string is shown in a scrollable text area contained in a JTextArea.

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