implements Closeable or implements AutoCloseable

AutoCloseable (introduced in Java 7) makes it possible to use the try-with-resources idiom:

public class MyResource implements AutoCloseable {

    public void close() throws Exception {
        System.out.println("Closing!");
    }

}

Now you can say:

try (MyResource res = new MyResource()) {
    // use resource here
}

and JVM will call close() automatically for you.

Closeable is an older interface. For some reason To preserve backward compatibility, language designers decided to create a separate one. This allows not only all Closeable classes (like streams throwing IOException) to be used in try-with-resources, but also allows throwing more general checked exceptions from close().

When in doubt, use AutoCloseable, users of your class will be grateful.

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