这是什么错误 是tomcat环境变量设置的不对吗

主页面能够登陆 但是输入用户名和密码后 再登陆就显示如下
HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: java.lang.NullPointerException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:522)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

root cause

java.lang.NullPointerException
com.vere.manager.authorize.PermisionBean.checkLogin(PermisionBean.java:86)
org.apache.jsp.home.admin_jsp._jspS

tomcat 是什么 ？ tomcat启动错误 tomcat的404错误 TOMCAT HTTP500错误 tomcat配置错误 tomcat 404错误 tomcat 错误代号集 JSP+TOMCAT问题http500错误 tomcat的http status404错误 eclipse中启动tomcat错误