在Oracle 11.2.0.4中调用 javax.mail 发送邮件时可能会遇到以下错误：
ORA-29532: Java call terminated by uncaught Java exception: javax.mail.MessagingException: IOException while sending message;
nested exception is:
javax.activation.UnsupportedDataTypeException: no object DCH for MIME type multipart/mixed;
boundary="----=_Part_0_1760344884.1407394057461"
第一步：需要先grantq权限：
EXEC dbms_java.grant_permission( '<your_schema_please_change>','SYS:java.lang.RuntimePermission', 'setContextClassLoader', '' );
第二步：解决方案看文档中。
