Regression on Statement.getGeneratedKeys() on UPDATE statements

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Properties;

import org.apache.derby.jdbc.EmbeddedDriver;

public class Derby {
    public static void main(String[] args) throws Exception {
        try (Connection c1 = new EmbeddedDriver().connect("jdbc:derby:memory:test;create=true", new Properties());
             Statement s = c1.createStatement()) {

            s.execute(
                "CREATE TABLE test ("
                    + "id INT PRIMARY KEY NOT NULL GENERATED ALWAYS AS IDENTITY,"
                    + "val INT)");

            try {
                s.executeUpdate("INSERT INTO test (val) VALUES (1)");

                try (PreparedStatement p = c1.prepareStatement("UPDATE test SET val = 2 WHERE id = 1", Statement.RETURN_GENERATED_KEYS)) {
                    p.executeUpdate();

                    try (ResultSet rs = p.getGeneratedKeys()) {
                        while (rs.next())
                            System.out.println(rs.getString(1));
                    }
                }
            }
            finally {
                s.execute("DROP TABLE test");
            }
        }
    }
}