What is the main function of the Closeable interface in Java?

The Closeable interface in Java is designed for objects that use resources requiring release (such as files, network connections). Its main function is the close() method, which closes the resource and releases associated system resources.

This allows objects to be used in a try-with-resources statement, ensuring automatic resource closure.

Example:

try (BufferedReader reader = new BufferedReader(new FileReader("file.txt"))) {
    String line = reader.readLine();
    System.out.println(line);
} // reader.close() is called automatically