我也碰到了和您同样的问题！
并且有：ava.sql.SQLException: Listener refused the connection with the following error:
ORA-12518, TNS:listener could not hand off client connection这个问题。
麻烦问您以下。该如何解决？
re: JSP彩色验证码 南战航 2007-02-06 15:56
好象这一句总是报异常
ImageIO.write(image, "JPEG", response.getOutputStream());