oracle外部java例程访问其它数据库的问题

oracle外部java例程访问其它数据库的问题
为什么总是返回error 也就是捕获了异常，我把它改成application程序 运行起来都是正确的呀！ 请各位大虾帮忙指点一下！程序如下： 
create or replace and compile java source named erptowms as
import java.sql.*;
import java.util.*;
public class ErpToWms
{
  public static String entry() throws Exception
  {
    ResultSet rs = null;
    Statement stmt = null;
    Connection conn = null;
    PreparedStatement pstmt = null;
                try {
                        Class.forName("com.mysql.jdbc.Driver").newInstance();
                        String url = "jdbc:mysql://localhost:3306/libdb";
                        Properties sysProps = System.getProperties();
                        sysProps.put("user", "root");
                        sysProps.put("password", "888");
                        conn = DriverManager.getConnection(url, sysProps);
                        
                        String strSql = "insert into login values('wei','hehe')";
                        
                        
                        pstmt = conn.prepareStatement(strSql);
                        
                        
                        
                        pstmt.executeUpdate();
                        
                
                                  return "ok";
                } catch (Exception e) {
                        e.printStackTrace();
                           return "error";
                } finally {
                        try {
                                if (null != rs)
                                        rs.close();                                if (null != pstmt)
                                        pstmt.close();
                 
                        
                                if (null != conn)
                                         conn.close();                        } catch (SQLException e) {
                                e.printStackTrace();
                        }
                }
  }
}