简单的代码，无法解决的异常

Question

con变量没有初始化。
你的代码里面有：
try
  {
   DriverManager.getConnection("jdbc:odbc:DataSource","sa","sa");
   Statement statement=con.createStatement
…………应该是：
con = DriverManager.getConnection("jdbc:odbc:DataSource","sa","sa");

Answer 1

exception javax.servlet.ServletException: tried to access method src.conndb.<init>()V from class org.apache.jsp.login_jsp
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:848)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:781)
org.apache.jsp.login_jsp._jspService(org.apache.jsp.login_jsp:97)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:322)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:291)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause java.lang.IllegalAccessError: tried to access method src.conndb.<init>()V from class org.apache.jsp.login_jsp
org.apache.jsp.login_jsp._jspService(org.apache.jsp.login_jsp:49)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:322)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:291)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)按照楼上的改了，又出现上面的问题，这类问题也是我操作数据库时常常发生的，我不知道怎么分析异常

Answer 2

private Connection con;
此项为定义
con=DriverManager.getConnection("jdbc:odbc:DataSource","sa","sa");