java.sql.Timestamp.toString() method works wrong when nanos = 0

This methods returns "1996-12-13 14:15:25." instead of
"1996-12-13 14:15:25.0" or "1996-12-13 14:15:25" or "1996-12-13 14:15:25.000000000"
(it is not clear from specification which result is correct)

==== Here is the test demonstrating the bug ====
import java.sql.Timestamp;
class java_sql_Timestamp6 {
  public static void main (String args[]) {
      Timestamp ts=Timestamp.valueOf("1996-12-13 14:15:25.0");
      System.out.println("ts = " + ts);
  }
}
=== Here is the test output ===
ts = 1996-12-13 14:15:25.