How can I use the “onchange” query in Java programming language?

 In the context of Java programming language the “on change” query refers to the use of listeners or event handlers in detecting the changes in input fields or its various components.

For instance, consider a scenario where you have a text field and you want to perform an action when your content make changes, then you can utilize a “Documentlistener” in Swing:-

Import javax.swing.*;

Import javax.swing.event.DocumentEvent;

Import javax.swing.event.DocumentListener;

Public class TextFieldOnChange {

    Public static void main(String[] args) {

        JFrame frame = new JFrame(“TextField OnChange Example”);

        JTextField textField = new JTextField();

        // Adding a DocumentListener to detect changes

        textField.getDocument().addDocumentListener(new DocumentListener() {

            @Override

            Public void insertUpdate(DocumentEvent e) {

                // Action to perform when text is inserted

                System.out.println(“Text inserted: “ + textField.getText());

            }

            @Override

            Public void removeUpdate(DocumentEvent e) {

                // Action to perform when text is removed

                System.out.println(“Text removed”);

            }

            @Override

            Public void changedUpdate(DocumentEvent e) {

                // Not used for plain text components

            }

        });

        Frame.add(textField);

        Frame.setSize(300, 200);

        Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        Frame.setVisible(true);

    }

}

In this above example the “Documnetlistener” is used to monitor the changes in the text field. Moreover, the “insertupdate()” and “removeupdate()” are invoked when a text is inserted or removed respectively.