Collections.sort(List) usage

One common mistake that people do while using the Collection.sort() method is that they try to sort a list whose members do not implement Comparable interface.

The method internally tries to delegate the comparision logic to the object itself by first casting it to a Comparable. You have to implement this interface in order to use this sort() routine.

The other option is to pass an explicit Comparator in the other sort(List, Comparator) routine.

HTTP Status 500 - Internal Server Error


type Exception report

message Internal Server Error

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

exception

org.apache.jasper.JasperException: net.vineetpriyanka.cars.Make
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:207)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:240)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:187)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:627)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:518)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:448)
at org.apache.jsp.viewMap_jsp._jspService(viewMap_jsp.java:71)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:92)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:162)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:240)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:187)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:200)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at net.vineetpriyanka.users.web.GroupSecurityFilter.doFilter(GroupSecurityFilter.java:35)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at net.vineetpriyanka.web.VPSessionFilter.doFilter(VPSessionFilter.java:50)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at net.vineetpriyanka.web.AccessLogFilter.doFilter(AccessLogFilter.java:31)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at net.vineetpriyanka.web.HibernateSessionFilter.doFilter(HibernateSessionFilter.java:27)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:209)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:144)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:445)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2358)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:133)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:118)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:116)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:534)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:127)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.ajp.tomcat4.Ajp13Processor.process(Ajp13Processor.java:409)
at org.apache.ajp.tomcat4.Ajp13Processor.run(Ajp13Processor.java:528)
at java.lang.Thread.run(Thread.java:595)

root cause

java.lang.ClassCastException: net.vineetpriyanka.cars.Make
at java.util.Collections.sort(Collections.java:121)
at org.apache.jsp.viewPrimitiveMap_jsp._jspService(viewPrimitiveMap_jsp.java:141)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:92)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:162)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:240)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:187)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:627)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:518)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:448)
at org.apache.jsp.viewMap_jsp._jspService(viewMap_jsp.java:71)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:92)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:162)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:240)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:187)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:200)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at net.vineetpriyanka.users.web.GroupSecurityFilter.doFilter(GroupSecurityFilter.java:35)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at net.vineetpriyanka.web.VPSessionFilter.doFilter(VPSessionFilter.java:50)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at net.vineetpriyanka.web.AccessLogFilter.doFilter(AccessLogFilter.java:31)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at net.vineetpriyanka.web.HibernateSessionFilter.doFilter(HibernateSessionFilter.java:27)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:209)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:144)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:445)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2358)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:133)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:118)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:116)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:534)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:127)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.ajp.tomcat4.Ajp13Processor.process(Ajp13Processor.java:409)
at org.apache.ajp.tomcat4.Ajp13Processor.run(Ajp13Processor.java:528)
at java.lang.Thread.run(Thread.java:595)

Apache Tomcat/4.1