What are the advantages of anonymous inner classes in Java?

Anonymous inner classes are used in Java as special inner classes that facilitate subclassing, simplifying code, and handling events (such as button clicks). Practical cases include: Event handling: Use anonymous inner classes to add click event listeners for buttons. Data transformation: Sort collections using the Collections.sort method and an anonymous inner class as a comparator.

Java Anonymous Internal Classes: Advantages and Practical Cases

Anonymous internal classes are a special type of internal class in Java. It is easy to create and use without explicitly defining a class name. They have the following advantages:

• Flexible creation of subclasses:Anonymous inner classes allow instances of subclasses to be quickly created when needed without having to define a separate class.
• Simplify code: Compared with using ordinary inner classes, anonymous inner classes can reduce code redundancy and improve readability.
• Event handling: Anonymous inner classes are often used for event handling because it allows programmers to quickly create listener classes or use GUI libraries such as Java Swing.

Practical case

Event processing: button click event

Assume there is a Button Class, contains a addActionListener method, which can receive an ActionListener parameter. Here is an example of using an anonymous inner class to add a click event listener for a button:

Button button = new Button();
button.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent event) {
        // 单击事件代码
    }
});

In this example, the actionPerformed method of the ActionListener interface has been overridden , used to define the action to be performed when the button is clicked.

Data conversion: Using Collections.sort

The Collections.sort method uses a Comparator to sort the collection. Here is an example of using an anonymous inner class as a comparator:

List<String> names = Arrays.asList("John", "Alice", "Bob");
Collections.sort(names, new Comparator<String>() {
    @Override
    public int compare(String o1, String o2) {
        return o1.compareTo(o2);
    }
});

In this example, the anonymous inner class implements the compare method of the Comparator interface for Sorts the names list based on string length.

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