Java Swing | JTextArea

JTextArea is a part of java Swing package . It represents a multi line area that displays text. It is used to edit the text . 
JTextArea inherits JComponent class. The text in JTextArea can be set to different available fonts and can be appended to new text . A text area can be customized to the need of user .
Constructors of JTextArea are: 

1. JTextArea() : constructs a new blank text area .
   
2. JTextArea(String s) : constructs a new text area with a given initial text.
   
3. JTextArea(int row, int column) : constructs a new text area with a given number of rows and columns.
   
4. JTextArea(String s, int row, int column) : constructs a new text area with a given number of rows and columns and a given initial text.
   

Commonly used methods :

1. append(String s) : appends the given string to the text of the text area.
   
2. getLineCount() : get number of lines in the text of text area.
   
3. setFont(Font f) : sets the font of text area to the given font. 
   
4. setColumns(int c) : sets the number of columns of the text area to given integer.
   
5. setRows(int r) : sets the number of rows of the text area to given integer.
   
6. getColumns() : get the number of columns of text area.
   
7. getRows() : get the number of rows of text area.
   

1. Program to create a simple JTextArea

Java

// Java Program to create a simple JTextArea
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
class text extends JFrame implements ActionListener {

    // JFrame
    static JFrame f;

    // JButton
    static JButton b;

    // label to display text
    static JLabel l;

    // text area
    static JTextArea jt;

    // default constructor
    text()
    {
    }

    // main class
    public static void main(String[] args)
    {
        // create a new frame to store text field and button
        f = new JFrame("textfield");

        // create a label to display text
        l = new JLabel("nothing entered");

        // create a new button
        b = new JButton("submit");

        // create a object of the text class
        text te = new text();

        // addActionListener to button
        b.addActionListener(te);

        // create a text area, specifying the rows and columns
        jt = new JTextArea(10, 10);

        JPanel p = new JPanel();

        // add the text area and button to panel
        p.add(jt);
        p.add(b);
        p.add(l);

        f.add(p);
        // set the size of frame
        f.setSize(300, 300);

        f.show();
    }

    // if the button is pressed
    public void actionPerformed(ActionEvent e)
    {
        String s = e.getActionCommand();
        if (s.equals("submit")) {
            // set the text of the label to the text of the field
            l.setText(jt.getText());
        }
    }
}

Output: 

2. Program to create a JTextArea and set a initial text and add buttons to change the font of text area.

Java

// Java Program  to create a JTextArea and
// set a initial text and add buttons to change
// the font of text area.
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
class text11 extends JFrame implements ActionListener {

    // JFrame
    static JFrame f;

    // JButton
    static JButton b, b1, b2, b3;

    // label to display text
    static JLabel l, l1;

    // text area
    static JTextArea jt;

    // default constructor
    text11()
    {
    }

    // main class
    public static void main(String[] args)
    {
        // create a new frame to store text field and button
        f = new JFrame("textfield");

        // create a label to display text
        l = new JLabel("nothing entered");
        l1 = new JLabel("0 lines");

        // create a new buttons
        b = new JButton("submit");
        b1 = new JButton("plain");
        b2 = new JButton("italic");
        b3 = new JButton("bold");

        // create a object of the text class
        text11 te = new text11();

        // addActionListener to button
        b.addActionListener(te);
        b1.addActionListener(te);
        b2.addActionListener(te);
        b3.addActionListener(te);

        // create a text area, specifying the rows and columns
        jt = new JTextArea("please write something ", 10, 10);

        JPanel p = new JPanel();

        // add the text area and button to panel
        p.add(jt);
        p.add(b);
        p.add(b1);
        p.add(b2);
        p.add(b3);
        p.add(l);
        p.add(l1);

        f.add(p);
        // set the size of frame
        f.setSize(300, 300);

        f.show();
    }

    // if the button is pressed
    public void actionPerformed(ActionEvent e)
    {
        String s = e.getActionCommand();
        if (s.equals("submit")) {
            // set the text of the label to the text of the field
            l.setText(jt.getText() + ", ");
            l1.setText(jt.getLineCount() + " lines");
        }
        else if (s.equals("bold")) {

            // set bold font
            Font f = new Font("Serif", Font.BOLD, 15);
            jt.setFont(f);
        }
        else if (s.equals("italic")) {
            // set italic font
            Font f = new Font("Serif", Font.ITALIC, 15);
            jt.setFont(f);
        }
        else if (s.equals("plain")) {
            // set plain font
            Font f = new Font("Serif", Font.PLAIN, 15);
            jt.setFont(f);
        }
    }
}

Output :

Note : The following program might not run in an online compiler please use an offline IDE