What Is JComboBox In Java?

JComboBox in Java is a part of the Swing library and is used to create a dropdown list that allows the user to select an item from a predefined set of options. It combines the functionality of a combo box (a drop-down list) with the ability to select items either by clicking on the list or typing in the input field.

Here are key features of JComboBox:

1. Dropdown List: It displays a list of items for the user to choose from.
2. Editable or Non-Editable: JComboBox can be configured to either allow the user to type a value (editable) or limit them to selecting from the dropdown list (non-editable).
3. Customizable Items: You can add custom items, including any objects, to the combo box.
4. Event Handling: You can register listeners to capture the selection event, enabling you to perform actions based on the user’s choice.

Basic Usage Example:

import javax.swing.*;

public class ComboBoxExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("JComboBox Example");
        String[] items = {"Apple", "Banana", "Orange"};
        JComboBox<String> comboBox = new JComboBox<>(items);

        comboBox.addActionListener(e -> {
            String selectedItem = (String) comboBox.getSelectedItem();
            System.out.println("Selected item: " + selectedItem);
        });

        frame.add(comboBox);
        frame.setSize(300, 200);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

Key Methods:

• addItem(Object item): Adds an item to the combo box.
• removeItem(Object item): Removes a specific item.
• getSelectedItem(): Returns the currently selected item.
• setEditable(boolean editable): Sets whether the combo box allows user input.

In summary, JComboBox is a versatile Swing component used to provide a drop-down list of options, making it a useful tool for user interfaces where a choice from a limited set of options is required.