Decorator pattern implementstions - extends vs implements

I create decorator pattern example:

interface:

public interface Printer {
  void print(String message);
}

implementation:

public class StringPrinter implements Printer {

  public void print(String message) {
    System.out.println(message);
  }
}

and 2 decorators:

change string to upper case:

public class UpCasePrinter implements Printer {

  private Printer printer;

  public UpCasePrinter(Printer printer) {
    this.printer = printer;
  }

  public void print(String message) {
    printer.print(message.toUpperCase());
  }
}

print reverse string:

public class InversePrinter implements Printer {

  private Printer printer;

  public InversePrinter(Printer printer) {
    this.printer = printer;
  }

  public void print(String message) {
    StringBuilder builder = new StringBuilder(message);
    printer.print(builder.reverse().toString());
  }
}

All worck fine. But when I reading examples on different sites I faind another implementations. Each decarator extends from another. And I saw the realization of BufferedInputStream

BufferedInputStream extends FilterInputStream
FilterInputStream extends InputStream
public abstract class InputStream implements Closeable

I can not understand the following:

1. Is there a difference in how to create a decorator? as for me - the decorator implements the same interface as the original class or as in the examples - the decorator is extends from another decorator, etc.

2. may be in the example with the BufferedInputStream such a realization only because the abstract class was chosen at the start and not the interface?