EXTERNAL NAME 参数的格式是什么？

当cl带有方法的 Java 类mth驻留在包pck中时，我应该在EXTERNAL NAME子句中放入什么CREATE PROCEDURE？

我试过了

CREATE PROCEDURE mth (arg1 INTEGER) LANGUAGE JAVA EXTERNAL NAME 'myjar:pck/cl.mth'
CREATE PROCEDURE mth (arg1 INTEGER) LANGUAGE JAVA EXTERNAL NAME 'myjar:pck.cl.mth'
CREATE PROCEDURE mth (arg1 INTEGER) LANGUAGE JAVA EXTERNAL NAME 'myjar:cl.mth'

但无论哪种方式，我得到The user defined function or procedure "mth" was unable to map to a single Java method.. SQLCODE=-20204, SQLSTATE=46008, DRIVER=3.68.61

在 Java 端，该方法声明如下：

public void send_mail( // with or w/o static, with or w/o synchronized
    final String P_TO,
    final String P_CC,
    final String P_BCC,
    final String P_FROM,
    final String P_SUBJECT,
    final String P_TEXT_MSG,
    final String P_HTML_MSG,
    final String P_ATTACH_NAME,
    final String P_ATTACH_MIME,
    final byte[] P_ATTACH_BLOB,
    final String P_SMTP_HOST,
    final int P_SMTP_PORT,
    final String P_USER_NAME,
    final String P_PASSWORD

在 DB2 端，正在尝试按如下方式创建该过程：

CREATE PROCEDURE send_mail(
  IN P_TO          VARCHAR(4096),
  IN P_CC          VARCHAR(4096) DEFAULT NULL,
  IN P_BCC         VARCHAR(4096) DEFAULT NULL,
  IN P_FROM        VARCHAR(4096),
  IN P_SUBJECT     VARCHAR(32672),
  IN P_TEXT_MSG    VARCHAR(32672) DEFAULT NULL,
  IN P_HTML_MSG    VARCHAR(32672) DEFAULT NULL,
  IN P_ATTACH_NAME VARCHAR(255) DEFAULT NULL,
  IN P_ATTACH_MIME VARCHAR(100) DEFAULT NULL,
  IN P_ATTACH_BLOB BLOB DEFAULT NULL,
  IN P_SMTP_HOST   VARCHAR(255),
  IN P_SMTP_PORT   INTEGER DEFAULT 25,
  IN P_USER_NAME   VARCHAR(255) DEFAULT NULL,
  IN P_PASSWORD    VARCHAR(32672) DEFAULT NULL
)
LANGUAGE java
PARAMETER STYLE java
FENCED THREADSAFE
EXTERNAL NAME 'javadb2:db2.smtp.send_mail' -- with or w/o db2

每次sqlj.db2_install_jar它出现在function\usernameDB2 文件夹层次结构中的文件夹下时，我都检查并再次检查。