In which version of Java was AutoCloseable introduced?

The AutoCloseable interface was introduced in Java starting from version 7 (Java SE 7). It allows objects to be automatically closed when used in a try-with-resources statement, simplifying resource management and preventing leaks.

Example of usage:

try (BufferedReader br = new BufferedReader(new FileReader("file.txt"))) {
    String line = br.readLine();
    System.out.println(line);
} catch (IOException e) {
    e.printStackTrace();
}

Here, BufferedReader implements AutoCloseable, and the resource is automatically closed after the try block.