JAVA出错了，不知道原因，谁给看看！

完成搞不懂，什么原因呢？

java.lang.IllegalStateException: Can't call invalidate() when session is
no longer valid.
at com.caucho.server.session.SessionImpl.invalidate(SessionImpl.java:519)
at com.caucho.server.session.SessionImpl.invalidate(SessionImpl.java:510)
at ctop.rapright.checkCrad(rapright.java:105)
at ctop.Encoding.sessionCreated(Encoding.java:42)
at com.caucho.server.session.SessionManager.handleCreateListeners(SessionManager.java:1390)
at com.caucho.server.session.SessionManager.createSession(SessionManager.java:1115)
at com.caucho.server.connection.AbstractHttpRequest.createSession(AbstractHttpRequest.java:1472)
at com.caucho.server.connection.AbstractHttpRequest.getSession(AbstractHttpRequest.java:1256)
at _jsp._login._loginpage__jsp._jspService(_loginpage__jsp.java:22)
at com.caucho.jsp.JavaPage.service(JavaPage.java:60)
at com.caucho.jsp.Page.pageservice(Page.java:570)
at com.caucho.server.dispatch.PageFilterChain.doFilter(PageFilterChain.java:179)
at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:173)
at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:229)
at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:274)
at com.caucho.server.port.TcpConnection.run(TcpConnection.java:511)
at com.caucho.util.ThreadPool.runTasks(ThreadPool.java:516)
at com.caucho.util.ThreadPool.run(ThreadPool.java:442)
at java.lang.Thread.run(Thread.java:619)

Can't call invalidate() when session is no longer valid.

char a = '98'; 因为 a 是字符型，字符型变量只能包含一个字符，'98' 包含了两个字符，所以报错。。 char a = 'a'; 这一句是没问题的。。