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Java Spring Error when page loaded maven html error

When I run the program I get an error:
2022-11-25 18:31:53.591 ERROR 8435 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.thymeleaf.exceptions.TemplateProcessingException: Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor' (template: "greeting" - line 15, col 23)] with root cause
java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'searchForm' available as request attribute
at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:153) ~[spring-webmvc-5.3.23.jar!/:5.3.23]
at org.springframework.web.servlet.support.RequestContext.getBindStatus(RequestContext.java:903) ~[spring-webmvc-5.3.23.jar!/:5.3.23]
at org.thymeleaf.spring5.context.webmvc.SpringWebMvcThymeleafRequestContext.getBindStatus(SpringWebMvcThymeleafRequestContext.java:227) ~[thymeleaf-spring5-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatusFromParsedExpression(FieldUtils.java:306) ~[thymeleaf-spring5-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:253) ~[thymeleaf-spring5-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:227) ~[thymeleaf-spring5-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.spring5.processor.AbstractSpringFieldTagProcessor.doProcess(AbstractSpringFieldTagProcessor.java:174) ~[thymeleaf-spring5-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:74) ~[thymeleaf-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.processor.element.AbstractElementTagProcessor.process(AbstractElementTagProcessor.java:95) ~[thymeleaf-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.util.ProcessorConfigurationUtils$ElementTagProcessorWrapper.process(ProcessorConfigurationUtils.java:633) ~[thymeleaf-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.engine.ProcessorTemplateHandler.handleStandaloneElement(ProcessorTemplateHandler.java:918) ~[thymeleaf-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.engine.StandaloneElementTag.beHandled(StandaloneElementTag.java:228) ~[thymeleaf-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.engine.TemplateModel.process(TemplateModel.java:136) ~[thymeleaf-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:661) ~[thymeleaf-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1098) ~[thymeleaf-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1072) ~[thymeleaf-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.spring5.view.ThymeleafView.renderFragment(ThymeleafView.java:366) ~[thymeleaf-spring5-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.thymeleaf.spring5.view.ThymeleafView.render(ThymeleafView.java:190) ~[thymeleaf-spring5-3.0.15.RELEASE.jar!/:3.0.15.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1405) ~[spring-webmvc-5.3.23.jar!/:5.3.23]
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1149) ~[spring-webmvc-5.3.23.jar!/:5.3.23]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1088) ~[spring-webmvc-5.3.23.jar!/:5.3.23]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:964) ~[spring-webmvc-5.3.23.jar!/:5.3.23]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.23.jar!/:5.3.23]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.23.jar!/:5.3.23]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:670) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.23.jar!/:5.3.23]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:779) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.68.jar!/:na]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.23.jar!/:5.3.23]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.23.jar!/:5.3.23]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.23.jar!/:5.3.23]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.23.jar!/:5.3.23]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.23.jar!/:5.3.23]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.23.jar!/:5.3.23]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1789) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-9.0.68.jar!/:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.68.jar!/:na]
at java.base/java.lang.Thread.run(Thread.java:1589) ~[na:na]
Although I did everything according to this guide: https://spring.io/guides/gs/validating-form-input/
Here is my code:
greeting.html
<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<title>Getting Started: Serving Web Content</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body bgcolor="#191724">
<center>
<h1 style="color: #e0def4;">
Hello!
</h1>
<form action="#" method="post" th:action="#{/}" th:object="${searchForm}">
<input type="text" th:field="*{search}">
<button type="submit">
Search
</button>
</form>
</center>
</body>
</html>
SearchForm.java
package org.privatec.coogle;
public class SearchForm {
private String search;
public String getSearch() {
return search;
}
public void setSearch(String search) {
this.search = search;
}
}
CoogleController.java
package org.privatec.coogle.Controllers;
import org.privatec.coogle.SearchForm;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
#Controller
public class PrivacoogleController {
#GetMapping("/")
public String greeting() {
return "greeting";
}
#PostMapping("/")
public void getPost(SearchForm searchForm) {
System.out.println(searchForm.getSearch());
}
}
I use: openjdk 19.0.1 2022-10-18 Apache Maven 3.8.6
I tried to replace the SearchForm.java and some of the elements in greeting.html, but I get the same error.

You didn't do everything according to the example.
Your get request doesn't contain the form.
It must be:
#Controller
public class PrivacoogleController {
#GetMapping("/")
public String greeting(SearchForm searchForm) {
return "greeting";
}
#PostMapping("/")
public void getPost(SearchForm searchForm) {
System.out.println(searchForm.getSearch());
}
}

Spring Cloud Stream - unable to serialize java class (works for java record)

Hi I am having an issue with new functional spring cloud stream...
I have a basic example:
#Autowired
private StreamBridge streamBridge;
#PostMapping("/publish/{topic}")
// fails
public boolean publish(#RequestBody MessageClass msg, #PathVariable String topic) {
// works
// public boolean publish(#RequestBody MessageRecord msg, #PathVariable String topic) {
return this.streamBridge.send(topic, msg);
}
Trying to simply as much as possible this is my java class:
public class MessageClass {
private String key;
private String content;
public MessageClass(String key, String content) {
this.key = key;
this.content = content;
}
public MessageClass() {
}
public String content() {
return content;
}
public String key() {
return key;
}
public void setKey(String key) {
this.key = key;
}
public void setContent(String content) {
this.content = content;
}
}
and record:
public record MessageRecord(String key, String content) {}
This fails for the MessageClass but succeeds with MessageRecord.
Relevant stack trace (I think, full below):
java.lang.ClassCastException: class io.enfuse.streamerrorexample.pkg.MessageClass cannot be cast to class [B (io.enfuse.streamerrorexample.pkg.MessageClass is in unnamed module of loader 'app'; [B is in module java.base of loader 'bootstrap')
at org.apache.kafka.common.serialization.ByteArraySerializer.serialize(ByteArraySerializer.java:19) ~[kafka-clients-3.1.1.jar:na]
See repo here: https://github.com/andyrewwer/spring-cloud-stream-error-example/settings/access
What is the difference between the java class and record and why does it work for record but not class?
Full stack trace:
2022-06-19 18:04:14.361 ERROR 70401 --- [nio-8080-exec-4] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.messaging.MessageHandlingException: error occurred in message handler [org.springframework.cloud.stream.binder.kafka.KafkaMessageChannelBinder$ProducerConfigurationMessageHandler#32e459ed]; nested exception is org.apache.kafka.common.errors.SerializationException: Can't convert value of class io.enfuse.streamerrorexample.pkg.MessageClass to class org.apache.kafka.common.serialization.ByteArraySerializer specified in value.serializer, failedMessage=GenericMessage [payload=io.enfuse.streamerrorexample.pkg.MessageClass#1dacd968, headers={id=fbe5d434-cd95-00b2-51ca-88a5f3b0f867, contentType=application/json, target-protocol=kafka, timestamp=1655687054356}]] with root cause
java.lang.ClassCastException: class io.enfuse.streamerrorexample.pkg.MessageClass cannot be cast to class [B (io.enfuse.streamerrorexample.pkg.MessageClass is in unnamed module of loader 'app'; [B is in module java.base of loader 'bootstrap')
at org.apache.kafka.common.serialization.ByteArraySerializer.serialize(ByteArraySerializer.java:19) ~[kafka-clients-3.1.1.jar:na]
at org.apache.kafka.common.serialization.Serializer.serialize(Serializer.java:62) ~[kafka-clients-3.1.1.jar:na]
at org.apache.kafka.clients.producer.KafkaProducer.doSend(KafkaProducer.java:954) ~[kafka-clients-3.1.1.jar:na]
at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:914) ~[kafka-clients-3.1.1.jar:na]
at org.springframework.kafka.core.DefaultKafkaProducerFactory$CloseSafeProducer.send(DefaultKafkaProducerFactory.java:993) ~[spring-kafka-2.8.6.jar:2.8.6]
at org.springframework.kafka.core.KafkaTemplate.doSend(KafkaTemplate.java:655) ~[spring-kafka-2.8.6.jar:2.8.6]
at org.springframework.kafka.core.KafkaTemplate.send(KafkaTemplate.java:429) ~[spring-kafka-2.8.6.jar:2.8.6]
at org.springframework.integration.kafka.outbound.KafkaProducerMessageHandler.handleRequestMessage(KafkaProducerMessageHandler.java:513) ~[spring-integration-kafka-5.5.12.jar:5.5.12]
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:136) ~[spring-integration-core-5.5.12.jar:5.5.12]
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:56) ~[spring-integration-core-5.5.12.jar:5.5.12]
at org.springframework.cloud.stream.binder.AbstractMessageChannelBinder$SendingHandler.handleMessageInternal(AbstractMessageChannelBinder.java:1074) ~[spring-cloud-stream-3.2.4.jar:3.2.4]
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:56) ~[spring-integration-core-5.5.12.jar:5.5.12]
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115) ~[spring-integration-core-5.5.12.jar:5.5.12]
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133) ~[spring-integration-core-5.5.12.jar:5.5.12]
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106) ~[spring-integration-core-5.5.12.jar:5.5.12]
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:72) ~[spring-integration-core-5.5.12.jar:5.5.12]
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:317) ~[spring-integration-core-5.5.12.jar:5.5.12]
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:272) ~[spring-integration-core-5.5.12.jar:5.5.12]
at org.springframework.cloud.stream.function.StreamBridge.send(StreamBridge.java:235) ~[spring-cloud-stream-3.2.4.jar:3.2.4]
at org.springframework.cloud.stream.function.StreamBridge.send(StreamBridge.java:170) ~[spring-cloud-stream-3.2.4.jar:3.2.4]
at org.springframework.cloud.stream.function.StreamBridge.send(StreamBridge.java:150) ~[spring-cloud-stream-3.2.4.jar:3.2.4]
at io.enfuse.streamerrorexample.pkg.StreamService.publish(StreamService.java:23) ~[main/:na]
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:577) ~[na:na]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.20.jar:5.3.20]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.20.jar:5.3.20]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.20.jar:5.3.20]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.20.jar:5.3.20]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.20.jar:5.3.20]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.20.jar:5.3.20]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.20.jar:5.3.20]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.20.jar:5.3.20]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.20.jar:5.3.20]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.3.20.jar:5.3.20]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:681) ~[tomcat-embed-core-9.0.63.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.20.jar:5.3.20]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.63.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.63.jar:9.0.63]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.20.jar:5.3.20]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.20.jar:5.3.20]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.20.jar:5.3.20]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.20.jar:5.3.20]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.20.jar:5.3.20]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.20.jar:5.3.20]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:890) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1743) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
at java.base/java.lang.Thread.run(Thread.java:833) ~[na:an]

Not able to stop a JMS consumer in Spring Boot with JmsListenerEndpointRegistry

MqStartStopDemoApplication.java
#SpringBootApplication
public class MqStartStopDemoApplication implements CommandLineRunner {
#Autowired
private Queue queue;
#Autowired
private JmsTemplate jmsTemplate;
public static void main(String[] args) {
SpringApplication.run(MqStartStopDemoApplication.class, args);
}
#Override
public void run(String... args) throws InterruptedException {
while (true) {
jmsTemplate.convertAndSend(queue, "Hello");
Thread.currentThread().sleep(1000);
}
}
}
JMSConfig.java
#Configuration
#EnableJms
public class JMSConfig {
#Bean
public Queue queue() {
return new ActiveMQQueue("simple-jms-queue");
}
}
Consumer.java
#Component
public class Consumer {
#JmsListener(destination = "simple-jms-queue")
public void listener(String msg) {
System.out.println("Received Message : " + msg);
}
}
JmsController.java
#RestController
#RequestMapping("/jms")
public class JmsController {
#Autowired
ApplicationContext context;
#RequestMapping(value = "/halt", method = RequestMethod.GET)
public #ResponseBody
String haltJmsListener() {
JmsListenerEndpointRegistry customRegistry = context.getBean("consumer", JmsListenerEndpointRegistry.class);
customRegistry.stop();
return "Jms Listener Stopped";
}
...
}
When I run the application and then hit http://localhost:8080/jms/halt
Error Log:
Received Message : Hello
Received Message : Hello
Received Message : Hello
Received Message : Hello
Received Message : Hello
Received Message : Hello
Received Message : Hello
Received Message : Hello
2021-11-02 11:52:12.002 INFO 8804 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-11-02 11:52:12.002 INFO 8804 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2021-11-02 11:52:12.002 INFO 8804 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 0 ms
2021-11-02 11:52:12.037 ERROR 8804 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'consumer' is expected to be of type 'org.springframework.jms.config.JmsListenerEndpointRegistry' but was actually of type 'com.example.demo.Consumer'] with root cause
org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'consumer' is expected to be of type 'org.springframework.jms.config.JmsListenerEndpointRegistry' but was actually of type 'com.example.demo.Consumer'
at org.springframework.beans.factory.support.AbstractBeanFactory.adaptBeanInstance(AbstractBeanFactory.java:417) ~[spring-beans-5.3.12.jar:5.3.12]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:398) ~[spring-beans-5.3.12.jar:5.3.12]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:213) ~[spring-beans-5.3.12.jar:5.3.12]
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1160) ~[spring-context-5.3.12.jar:5.3.12]
at com.example.demo.JmsController.haltJmsListener(JmsController.java:22) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.12.jar:5.3.12]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.12.jar:5.3.12]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.54.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.12.jar:5.3.12]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.54.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.12.jar:5.3.12]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.12.jar:5.3.12]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.12.jar:5.3.12]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.12.jar:5.3.12]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.12.jar:5.3.12]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.12.jar:5.3.12]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:895) [tomcat-embed-core-9.0.54.jar:9.0.54]

What makes you think the registry is a bean named consumer?
The registry has a reference to each listener container created for each JmsListener.
Just use
JmsListenerEndpointRegistry customRegistry = context.getBean(JmsListenerEndpointRegistry.class);
instead.
The actual bean name is JmsListenerConfigUtils.JMS_LISTENER_ENDPOINT_REGISTRY_BEAN_NAME ("org.springframework.jms.config.internalJmsListenerEndpointRegistry").

How to solve "java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'taxForm' available as request attribute"

I'm currently trying to implement a form in HTML using Thymeleaf and Spring. I'm following this tutorial as a reference. However, when I run the server and visit the page, I get a TemplateProcessingError.
Project code
Model:
public class TaxForm {
private String status;
private float salary;
public TaxForm() {
}
public TaxForm(String status, float salary) {
this.status = status;
this.salary = salary;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public float getSalary() {
return salary;
}
public void setSalary(float salary) {
this.salary = salary;
}
#Override
public String toString() {
return "TaxForm{" +
"status='" + status + '\'' +
", salary=" + salary +
'}';
}
Controller
import com.github.kyleryvn.formsubmissiondemo.model.TaxForm;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PostMapping;
#Controller
public class ProjectController {
#GetMapping("/tax-service")
public String createProjectForm(Model model) {
model.addAttribute("taxForm", new TaxForm());
return "index";
}
#PostMapping("/result")
public String displayFormResults(#ModelAttribute TaxForm taxForm) {
return "result";
}
}
Template
index.html
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" type="text/css" th:href="#{format.css}">
</head>
<body>
<form th:action="#{/tax-service}" th:object="${taxForm}" method="post">
<label>Status</label>
<input type="text" th:field="*{status}">
<label>Salary $</label>
<input type="number" th:field="*{salary}">
</form>
</body>
</html>
result.html
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<p>Status: <span th:text="${taxForm.status}"></span></p>
<p>Status: <span th:text="${taxForm.salary}"></span></p>
<a th:href="#{/tax-service}">Add new project</a>
</body>
</html>
Error Message
org.thymeleaf.exceptions.TemplateProcessingException: Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor' (template: "index" - line 12, col 28)
at org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:117) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.processor.element.AbstractElementTagProcessor.process(AbstractElementTagProcessor.java:95) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.util.ProcessorConfigurationUtils$ElementTagProcessorWrapper.process(ProcessorConfigurationUtils.java:633) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.engine.ProcessorTemplateHandler.handleStandaloneElement(ProcessorTemplateHandler.java:918) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.engine.StandaloneElementTag.beHandled(StandaloneElementTag.java:228) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.engine.TemplateModel.process(TemplateModel.java:136) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:661) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1098) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1072) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.view.ThymeleafView.renderFragment(ThymeleafView.java:366) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.view.ThymeleafView.render(ThymeleafView.java:190) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1396) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1141) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1080) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.8.jar:5.3.8]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.48.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.8.jar:5.3.8]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.48.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:228) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.8.jar:5.3.8]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.8.jar:5.3.8]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.8.jar:5.3.8]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.8.jar:5.3.8]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.8.jar:5.3.8]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.8.jar:5.3.8]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1723) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at java.base/java.lang.Thread.run(Thread.java:831) ~[na:na]
Caused by: java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'taxForm' available as request attribute
at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:153) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.support.RequestContext.getBindStatus(RequestContext.java:903) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.thymeleaf.spring5.context.webmvc.SpringWebMvcThymeleafRequestContext.getBindStatus(SpringWebMvcThymeleafRequestContext.java:227) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatusFromParsedExpression(FieldUtils.java:306) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:253) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:227) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.processor.AbstractSpringFieldTagProcessor.doProcess(AbstractSpringFieldTagProcessor.java:174) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:74) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
... 52 common frames omitted
2021-06-29 23:24:15.134 ERROR 1008 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.thymeleaf.exceptions.TemplateProcessingException: Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor' (template: "index" - line 12, col 28)] with root cause
java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'taxForm' available as request attribute
at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:153) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.support.RequestContext.getBindStatus(RequestContext.java:903) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.thymeleaf.spring5.context.webmvc.SpringWebMvcThymeleafRequestContext.getBindStatus(SpringWebMvcThymeleafRequestContext.java:227) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatusFromParsedExpression(FieldUtils.java:306) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:253) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:227) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.processor.AbstractSpringFieldTagProcessor.doProcess(AbstractSpringFieldTagProcessor.java:174) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:74) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.processor.element.AbstractElementTagProcessor.process(AbstractElementTagProcessor.java:95) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.util.ProcessorConfigurationUtils$ElementTagProcessorWrapper.process(ProcessorConfigurationUtils.java:633) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.engine.ProcessorTemplateHandler.handleStandaloneElement(ProcessorTemplateHandler.java:918) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.engine.StandaloneElementTag.beHandled(StandaloneElementTag.java:228) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.engine.TemplateModel.process(TemplateModel.java:136) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:661) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1098) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1072) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.view.ThymeleafView.renderFragment(ThymeleafView.java:366) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.thymeleaf.spring5.view.ThymeleafView.render(ThymeleafView.java:190) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1396) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1141) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1080) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.8.jar:5.3.8]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.8.jar:5.3.8]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.48.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.8.jar:5.3.8]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.48.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:228) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.8.jar:5.3.8]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.8.jar:5.3.8]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.8.jar:5.3.8]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.8.jar:5.3.8]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.8.jar:5.3.8]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.8.jar:5.3.8]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1723) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at java.base/java.lang.Thread.run(Thread.java:831) ~[na:na]
Any help would be appreciated to solve it. Many of the tutorials I've seen online follow similar patterns, so I would like to know if I'm doing something wrong

java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'taxForm' available as request attribute
taxForm object was null causes error. You must check null before usage, or assurance it is never null.

Make all these changes and your code will work fine.
In ProjectController
#Controller
public class ProjectController {
#GetMapping("/")
public String createProjectForm(Model model) {
model.addAttribute("taxForm", new TaxForm());
return "index";
}
#PostMapping("/tax-service")
public String displayFormResult(#ModelAttribute TaxForm taxForm, Model model) {
model.addAttribute("taxForm", taxForm);
return "result";
}
}
In index.html
<form th:action="#{/tax-service}" th:object="${taxForm}" method="post">
<label>Status</label>
<input type="text" th:field="*{status}">
<label>Salary $</label>
<input type="number" th:field="*{salary}">
<input type="submit">
</form>
In result.html
<body>
<p>Status: <span th:text="${taxForm.status}"></span></p>
<p>Status: <span th:text="${taxForm.salary}"></span></p>
<a th:href="#{/}">Add new project</a>
</body>

Binding result gives Whitelabel Error Page

I have a thymeleaf form where i can add a subcategory to a parent category:
<div th:if="${parentCategories.size() == 0}">
<span>There are no categories, please, add some categories!</span>
</div>
<div th:unless="${parentCategories.size() == 0}">
<label for="subcategoryForm">Add a subcategory</label>
<form id="subcategoryForm" th:action="#{/category/add-subcategory}" th:object="${category}" method="post">
<label for="name">Category name</label>
<input id="name" type="text" th:field="*{categoryName}"/>
<span th:if="${#fields.hasErrors('categoryName')}" th:errors="*{categoryName}" th:errorclass="error"></span>
<label for="selectParentCategory">Enter a parent category</label>
<select id="selectParentCategory" th:field="*{parentCategoryName}">
<option th:each="category : ${parentCategories}"
th:value="${category.categoryName}"
th:text="${category.categoryName}"/>
<span th:if="${#fields.hasErrors('parentCategoryName')}" th:errors="*{parentCategoryName}" th:errorclass="error"></span>
</select>
<button type="submit">Add category</button>
</form>
</div>
I have a CategoryDTO:
#Setter
#Getter
public class CategoryDTO {
#CategoryValidator
private String categoryName;
#ParentCategoryValidator
private String parentCategoryName;
}
That #CategoryValidator is validated by CategoryValidatorImpl:
#Autowired
private CategoryRepository categoryRepository;
#Override
public boolean isValid(String value, ConstraintValidatorContext context) {
if(value.isBlank()){
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate("{categoryDTO.blank}").addConstraintViolation();
return false;
}
Optional<Category> optionalCategory = categoryRepository.findByName(value);
if (optionalCategory.isPresent()) {
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate("{categoryDTO.alreadyExists}").addConstraintViolation();
return false;
}
Pattern pattern = Pattern.compile("[a-zA-Z\\s]*");
Matcher matcher = pattern.matcher(value);
if (!matcher.matches()) {
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate("{categoryDTO.name.invalid}").addConstraintViolation();
return false;
}
return true;
}
And a part of CategoryController:
#GetMapping("/subcategory-form")
public String getSubcategoryForm(Model model){
List<CategoryDTO> listOfParentCategories = categoryService.getParentCategories();
model.addAttribute("category", new CategoryDTO());
model.addAttribute("parentCategories", listOfParentCategories);
return "add-subcategory-form";
}
#PostMapping("/add-subcategory")
public String addSubcategory(#Valid #ModelAttribute("category") CategoryDTO categoryDTO, BindingResult bindingResult){
if(bindingResult.hasErrors()){
return "add-subcategory-form";
}
categoryService.add(categoryDTO);
return "redirect:/category/subcategory-form";
}
In the input field when i enter a blank, the validator discovers it properly using hasErrors in the controller, but when i'm returning the form after discovering the blank and returning false, it gives this:
Whitelabel Error Page This application has no explicit mapping for
/error, so you are seeing this as a fallback.
Wed Nov 18 13:45:26 EET 2020 There was an unexpected error
(type=Internal Server Error, status=500). An error happened during
template parsing (template: "class path resource
[templates/add-subcategory-form.html]")
org.thymeleaf.exceptions.TemplateInputException: An error happened
during template parsing (template: "class path resource
[templates/add-subcategory-form.html]") at
org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parse(AbstractMarkupTemplateParser.java:241)
at
org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parseStandalone(AbstractMarkupTemplateParser.java:100)
at
org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:666)
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1098) at
org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1072) at
org.thymeleaf.spring5.view.ThymeleafView.renderFragment(ThymeleafView.java:362)
at
org.thymeleaf.spring5.view.ThymeleafView.render(ThymeleafView.java:189)
at
org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1373)
at
org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1118)
at
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1057)
at
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
at
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
at
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:652) at
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at
org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at
org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at
org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:93)
at
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
at
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
at
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374)
at
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
at
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590)
at
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:834) Caused by:
org.attoparser.ParseException: Exception evaluating SpringEL
expression: "parentCategories.size() == 0" (template:
"add-subcategory-form" - line 13, col 10) at
org.attoparser.MarkupParser.parseDocument(MarkupParser.java:393) at
org.attoparser.MarkupParser.parse(MarkupParser.java:257) at
org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parse(AbstractMarkupTemplateParser.java:230)
... 52 more Caused by:
org.thymeleaf.exceptions.TemplateProcessingException: Exception
evaluating SpringEL expression: "parentCategories.size() == 0"
(template: "add-subcategory-form" - line 13, col 10) at
org.thymeleaf.spring5.expression.SPELVariableExpressionEvaluator.evaluate(SPELVariableExpressionEvaluator.java:290)
at
org.thymeleaf.standard.expression.VariableExpression.executeVariableExpression(VariableExpression.java:166)
at
org.thymeleaf.standard.expression.SimpleExpression.executeSimple(SimpleExpression.java:66)
at
org.thymeleaf.standard.expression.Expression.execute(Expression.java:109)
at
org.thymeleaf.standard.expression.Expression.execute(Expression.java:138)
at
org.thymeleaf.standard.expression.Expression.execute(Expression.java:125)
at
org.thymeleaf.standard.processor.StandardIfTagProcessor.isVisible(StandardIfTagProcessor.java:59)
at
org.thymeleaf.standard.processor.AbstractStandardConditionalVisibilityTagProcessor.doProcess(AbstractStandardConditionalVisibilityTagProcessor.java:61)
at
org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:74)
at
org.thymeleaf.processor.element.AbstractElementTagProcessor.process(AbstractElementTagProcessor.java:95)
at
org.thymeleaf.util.ProcessorConfigurationUtils$ElementTagProcessorWrapper.process(ProcessorConfigurationUtils.java:633)
at
org.thymeleaf.engine.ProcessorTemplateHandler.handleOpenElement(ProcessorTemplateHandler.java:1314)
at
org.thymeleaf.engine.TemplateHandlerAdapterMarkupHandler.handleOpenElementEnd(TemplateHandlerAdapterMarkupHandler.java:304)
at
org.thymeleaf.templateparser.markup.InlinedOutputExpressionMarkupHandler$InlineMarkupAdapterPreProcessorHandler.handleOpenElementEnd(InlinedOutputExpressionMarkupHandler.java:278)
at
org.thymeleaf.standard.inline.OutputExpressionInlinePreProcessorHandler.handleOpenElementEnd(OutputExpressionInlinePreProcessorHandler.java:186)
at
org.thymeleaf.templateparser.markup.InlinedOutputExpressionMarkupHandler.handleOpenElementEnd(InlinedOutputExpressionMarkupHandler.java:124)
at
org.attoparser.HtmlElement.handleOpenElementEnd(HtmlElement.java:109)
at
org.attoparser.HtmlMarkupHandler.handleOpenElementEnd(HtmlMarkupHandler.java:297)
at
org.attoparser.MarkupEventProcessorHandler.handleOpenElementEnd(MarkupEventProcessorHandler.java:402)
at
org.attoparser.ParsingElementMarkupUtil.parseOpenElement(ParsingElementMarkupUtil.java:159)
at org.attoparser.MarkupParser.parseBuffer(MarkupParser.java:710) at
org.attoparser.MarkupParser.parseDocument(MarkupParser.java:301) ...
54 more Caused by:
org.springframework.expression.spel.SpelEvaluationException: EL1011E:
Method call: Attempted to call method size() on null context object
at
org.springframework.expression.spel.ast.MethodReference.throwIfNotNullSafe(MethodReference.java:154)
at
org.springframework.expression.spel.ast.MethodReference.getValueRef(MethodReference.java:83)
at
org.springframework.expression.spel.ast.CompoundExpression.getValueRef(CompoundExpression.java:70)
at
org.springframework.expression.spel.ast.CompoundExpression.getValueInternal(CompoundExpression.java:91)
at
org.springframework.expression.spel.ast.OpEQ.getValueInternal(OpEQ.java:42)
at
org.springframework.expression.spel.ast.OpEQ.getValueInternal(OpEQ.java:32)
at
org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:112)
at
org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:337)
at
org.thymeleaf.spring5.expression.SPELVariableExpressionEvaluator.evaluate(SPELVariableExpressionEvaluator.java:263)
... 75 more
The thing is, for the other form of mine where i have to add just parent categories, if i add a blank, it returns the thymeleaf and prints the error message i wrote, but i can't figure this out for this form.

The stacktrace has the following hints on the problem:
Exception evaluating SpringEL expression: "parentCategories.size() == 0" (template: "add-subcategory-form" - line 13, col 10)
and:
Attempted to call method size() on null context object at
This means that parentCategories is not present anymore in the Thymeleaf context.
You need to re-add the parentCategories in the model again when there are errors:
#PostMapping("/add-subcategory")
public String addSubcategory(#Valid #ModelAttribute("category") CategoryDTO categoryDTO, BindingResult bindingResult) {
if(bindingResult.hasErrors()){
List<CategoryDTO> listOfParentCategories = categoryService.getParentCategories();
model.addAttribute("parentCategories", listOfParentCategories);
return "add-subcategory-form";
}
categoryService.add(categoryDTO);
return "redirect:/category/subcategory-form";
}