Spring restart end point using spring cloud context - java

I am trying to programmatically restart my spring boot application end point. Below is the lines I have used.
public class FileWatcher {
#Autowired
private RestartEndpoint restartEndpoint;
public void onFileChange() {
Thread restartThread = new Thread(() -> restartEndpoint.restart());
restartThread.setDaemon(false);
restartThread.start();
}
}
But it throws the below error.
Error:(32, 64) java: cannot access org.springframework.boot.actuate.endpoint.AbstractEndpoint
class file for org.springframework.boot.actuate.endpoint.AbstractEndpoint not found
What am I doing wrong here? Any help would be much appreciated.

http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#production-ready
Add the actuator dependencies, in maven:
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
</dependencies>
For Gradle, use the declaration:
dependencies {
compile("org.springframework.boot:spring-boot-starter-actuator")
}

Related

How to update a flag in existing running Spring Boot Application without restart

I have a spring boot application running a feature. I want to toggle that feature(on/off) at runtime without redeploying or restarting the application. Issue is that I can't deploy any rest endpoint as server has only exposed some specific port because of security.
I want to remotely control the toggle so that I can set that feature on and off. I tried reading the environment variable on my local machine using:
System.getEnv("envVariable")
but even after updating it using export envVariable=true it's not reflecting updated value in the code.
Can someone suggest any way to achieve this ?
Thanks,
To do this you need some more dependencies.
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Hoxton.SR9</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
in properties file you need to write
management.endpoints.web.exposure.include=*
and on the class wherever you are are using environment variables use Annotation #RefreshScope like
import org.springframework.web.bind.annotation.RestController;
import org.springframework.cloud.context.config.annotation.RefreshScope;
#RefreshScope
#RestController
public class DemoController {
#Value("${my.data}")
String str;
// code
}
and whenever you are changing environment variable just hit a post request http://localhost:PORT/actuator/refresh
using above configuration you can change the environment variables.
There is a programming pattern Feature Toggle that provides a way to turn on/off application components during the runtime. The core idea is to ask property files or database config table about current states of config fields and change application functionality if config changed. This pattern described here https://martinfowler.com/bliki/FeatureToggle.html. You can find more by using keyword "Feature Flags".
One of popular implementations of Feature Flags for Java is togglz (https://www.togglz.org/quickstart.html).
Here is an exaple of using togglz:
Create enum for features representation
public enum MyFeatures implements Feature {
#EnabledByDefault
#Label("First Feature")
FEATURE_ONE,
#Label("Second Feature")
FEATURE_TWO;
public boolean isActive() {
return FeatureContext.getFeatureManager().isActive(this);
}
Implement TogglzConfig
#ApplicationScoped
public class DemoConfiguration implements TogglzConfig {
public Class<? extends Feature> getFeatureClass() {
return MyFeatures.class;
}
public StateRepository getStateRepository() {
return new FileBasedStateRepository(new File("/tmp/features.properties"));
}
public UserProvider getUserProvider() {
return new ServletUserProvider("admin");
}
}
Describe the feature behavior depended on toggle:
if( MyFeatures.FEATURE_ONE.isActive() ) {
// new stuff here
}
Source: https://www.togglz.org/quickstart.html

Spring Boot 2.1 cache actuator not present

I have setup a simple spring boot application based on version 2.1 (https://github.com/dkellenb/spring-boot-2.1-cache-actuator-missing). I cannot find the reason why the cache actuator is not available at http://localhost:8080/actuator/caches .
#EnableCaching
#SpringBootApplication
#Controller
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
#Cacheable(cacheNames = "helloWorld")
#GetMapping
public ResponseEntity<String> hello() {
return ResponseEntity.ok("hello world");
}
}
And for the pom.xml i have added cache and actuator:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-cache</artifactId>
</dependency>
Also i have tested with
endpoints.caches.enabled=true
management.endpoints.web.exposure.include=info,health,cache
Note that Cache Actuator is available with JMX, but on on web.
The reason was:
cache is not exposed by default (see https://docs.spring.io/spring-boot/docs/current/reference/html/production-ready-endpoints.html#production-ready-endpoints-exposing-endpoints)
There was a typo for the exposure, it should be caches (plural)
I had a similar problem and it turned out that the actuator must be be in the version spring-boot-autoconfigure-2.1.3.RELEASE.jar.
My previous version was spring-boot-actuator-autoconfigure-2.0.2.RELEASE.jar. In this version CachesEndpointAutoConfiguration not exist. This class is responsible for creating the "cachesEndpoint" bean if the "cacheManager" bean is present in the application.
Try the version 2.1.3.

Spring boot validation annotations #Valid and #NotBlank not working

Given below is my main controller from which I am calling the getPDFDetails method.
#RequestMapping(value=PATH_PRINT_CONTRACTS, method=RequestMethod.POST)
public ResponseEntity<?> printContracts(#RequestBody final UpdatePrintContracts updatePrintContracts) throws Exception {
System.out.println("contracts value is "+ updatePrintContracts);
Integer cancellationReasons = service.getPDFDetails(updatePrintContracts);
System.out.println("success!");
return ResponseEntity.ok(cancellationReasons);
}
Below is the UpdatePrintContracts class where I have defined all the variables with validation annotations and corresponding getter/setter methods.
public class UpdatePrintContracts {
#Valid
#NotBlank
#Pattern(regexp = "\\p{Alnum}{1,30}")
String isReprint;
#Valid
#NotBlank
Integer dealerId;
#Valid
#NotBlank
#Pattern(regexp = "\\p{Alnum}{1,30}")
String includeSignatureCoordinates;
#Valid
#NotBlank
java.util.List<Integer> contractNumbers;
public String getIsReprint() {
return isReprint;
}
public void setIsReprint(String isReprint) {
this.isReprint = isReprint;
}
public Integer getDealerId() {
return dealerId;
}
public void setDealerId(Integer dealerId) {
this.dealerId = dealerId;
}
public String getIncludeSignatureCoordinates() {
return includeSignatureCoordinates;
}
public void setIncludeSignatureCoordinates(String includeSignatureCoordinates) {
this.includeSignatureCoordinates = includeSignatureCoordinates;
}
public java.util.List<Integer> getContractNumbers() {
return contractNumbers;
}
public void setContractNumbers(java.util.List<Integer> contractNumbers) {
this.contractNumbers = contractNumbers;
}
}
I am trying to run the application as a Spring Boot app by right clicking on the project (Run As) and passing blank values for variables isReprint and includeSignatureCoordinates through Soap UI. However the validation doesn't seem to work and is not throwing any validation error in Soap UI. What am I missing? Any help is appreciated!
If you are facing this problem in latest version of spring boot (2.3.0) make sure to add the following dependency:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
Observation:
In earlier version of Spring Boot (1.4.7), javax.validation used to work out of the box. But, after upgrading to latest version, annotations broke. Adding the following dependency alone doesn't work:
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
</dependency>
Because this provides JSR Specification but not the implementation. You can also use hibernate-validator instead of spring-boot-starter-validation.
For Anyone who is getting this issue with 2.0.1.Final:
In all SpringBoot versions above 2.2, Validations starter is not a part of web starter anymore
Check Notes here
So, all you have to do is add this dependency in your build.gradle/pom file
GRADLE:
implementation 'org.springframework.boot:spring-boot-starter-validation'
MAVEN
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
First you dont need to have #Valid annotation for those class variables in UpdatePrintContracts . You can delete them.
To trigger validation of a #Controller input, simply annotate the input argument as #Valid or #Validated:
#RequestMapping(value=PATH_PRINT_CONTRACTS, method=RequestMethod.POST)
public ResponseEntity<?> printContracts(#Valid #RequestBody final UpdatePrintContracts updatePrintContracts) throws Exception {
Refer here for full understanding of validating models in spring boot.
And If you want to check that a string contains only specific characters, you must add anchors (^ for beginning of the string, $ for end of the string) to be sure that your pattern matches all the string.Curly brackets are only to write a quantity,
#Pattern(regexp = "^[\\p{Alnum}]{1,32}$")
Lastly i assume you have following jars in your classpath,
.validation-api.jar (contains the abstract API and the annotation scanner)
.hibernate-validator.jar (contains the concrete implementation)
I faced the same error.
I had to use the below 2 dependencies alone:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
And use #Validated annotation(import org.springframework.validation.annotation.Validated) on rest controller level and #Valid annotation at method argument level(import javax.validation.Valid)
If there are any other extra dependencies like javax.validation.validation-api, org.hibernate.hibernate-validator, etc then the validations stopped working for me. So make sure that you remove these dependencies from pom.xml
I was using This dependency of validation in spring boot and didn't work ,
<!-- https://mvnrepository.com/artifact/javax.validation/validation-api -->
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>2.0.1.Final</version>
I replaced it with spring-boot-starter-validation and it worked .
<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-
starter-validation -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
<version>2.4.0</version>
this is for anyone here who still has the same issue after following the steps mentioned above. I had to restart my IDE (IntelliJ) for the changes to take effect.
My problem solved by this.
When we use classes inside classes that also need validations so #Valid needs to be annotated to all in that case.
Link for more details
Make sure to use #Valid annotation before #RequestBody
For newer versions of spring boot ensure all validation annotation are picked from jakarta.validation.* package and not javax.validation.*. As the annotations are named same in both.
Step-1: Add these two dependency in the pom.xml file
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
Step-2: Create a Custom Exception class like this
package com.bjit.salon.auth.service.exceptions;
import org.springframework.context.support.DefaultMessageSourceResolvable;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import java.util.List;
import java.util.stream.Collectors;
#ControllerAdvice
public class AnynameApplicationException {
#ExceptionHandler(MethodArgumentNotValidException.class)
#ResponseBody
public ResponseEntity<List<String>> processUnmergeException(final
MethodArgumentNotValidException ex) {
List<String> list = ex.getBindingResult().getAllErrors().stream()
.map(DefaultMessageSourceResolvable::getDefaultMessage)
.collect(Collectors.toList());
return new ResponseEntity<>(list, HttpStatus.BAD_REQUEST);
}
}
Step-3: Add #Valid annotation to the method arguments like this way
public ResponseEntity<?> registerAccount(#Valid #RequestBody UserRegisterDto
registerDto) {
// rest of the codes
}
You have to add this dependency in pom.xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
Note: SNAPSHOT, M1, M2, M3, and M4 releases typically WORK IN PROGRESS. The Spring team is still working on them, Recommend NOT using them.
You can use #NotEmpty will check for both blank and null values.
Add #Valid to your RestContoller class methods

How to make embedded mongodb keep the data on application shutdown?

I don't want to install the full mongodb, so I created a simple spring-boot application with the following pom:
<!-- This dependency is to have an embedded mongodb -->
<dependency>
<groupId>de.flapdoodle.embed</groupId>
<artifactId>de.flapdoodle.embed.mongo</artifactId>
<version>1.50.5</version>
</dependency>
<!-- while this provides a spring factory bean for the embedded mongodb -->
<dependency>
<groupId>cz.jirutka.spring</groupId>
<artifactId>embedmongo-spring</artifactId>
<version>RELEASE</version>
</dependency>
<!-- finally this one is the spring-boot starter for mongodb -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-mongodb</artifactId>
<version>${spring.boot.version}</version>
</dependency>
It works fine, but on the application shutdown I lose all the data stored.
I noticed that the db is created inside of a temporary folder under
C:\Users\myUser\AppData\Local\Temp\embedmongo-db-78beadc3-fa16-4101-afb1-ea7496f6f90c and, every time the application is restarted, another folder with different ID is created at the same location.
So, would it be possible to specify where the DB should be created so to keep the existing one and not lose all the data? Like you would do with h2 or sqllite?
Now it's possible see it.
Next code just shows my solution to implement it.
public class MongoInMemory {
private int port;
private String host;
private MongodProcess process = null;
public MongoInMemory(int port, String host){
this.port = port;
this.host = host;
}
#PostConstruct
public void init() throws IOException {
Storage storage = new Storage(
System.getProperty("user.home") + "/.ttraining-storage", null, 0);
IRuntimeConfig runtimeConfig = new RuntimeConfigBuilder()
.defaults(Command.MongoD)
.artifactStore(new ExtractedArtifactStoreBuilder()
.defaults(Command.MongoD)
.download(new DownloadConfigBuilder()
.defaultsForCommand(Command.MongoD).build())
.executableNaming(new UserTempNaming()))
.build();
IMongodConfig mongodConfig = new MongodConfigBuilder()
.version(Version.Main.PRODUCTION)
.net(new Net(host, port, false))
.replication(storage)
.build();
MongodStarter runtime = MongodStarter.getInstance(runtimeConfig);
process = runtime.prepare(mongodConfig).start();
}
#PreDestroy
public void stop(){
process.stop();
}
}
In configuration class define that as a bean
#Bean
public MongoInMemory mongoInMemory(
#Value("${spring.data.mongodb.port}") int port,
#Value("${spring.data.mongodb.host}") String host) {
return new MongoInMemory(port, host)
}
At last, remove embedded mongodb autoconfiguration in your entry point
#SpringBootApplication(exclude = EmbeddedMongoAutoConfiguration.class)
PS: Remove from dependecies cz.jirutka.spring:embedmongo-spring
PSS: Tested on Spring-boot 2.0.0.RELEASE
PSSS: Also you can define path as a property in application.properties and also it in constructor
The easiest way is to set the database-dir and oplog-size of the embedded mongo-db in the application.properties as described here: http://sahits.ch/blog/openpatrician/2017/05/20/embedded-databases-for-statistic-storage/
spring.mongodb.embedded.storage.database-dir=your-dir-name
spring.mongodb.embedded.storage.oplog-size=0
I needed this as well and it works like a charm. Tested with spring-boot 2.2.5.RELEASE and de.flapdoodle.embed.mongo 2.2.0

java.lang.IllegalArgumentException: No converter found for return value of type

With this code
#RequestMapping(value = "/bar/foo", method = RequestMethod.GET)
public ResponseEntity<foo> foo() {
Foo model;
...
return ResponseEntity.ok(model);
}
}
I get the following exception
java.lang.IllegalArgumentException: No converter found for return value of type
My guess is that the object cannot be converted to JSON because Jackson is missing. I don't understand why because I thought that Jackson was built in with spring boot.
Then I have tried to add Jackson to the pom.xml but I still have the same error
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.4.3</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.4.3</version>
</dependency>
Do I have to change any spring boot properties to make this work?
The problem was that one of the nested objects in Foo didn't have any getter/setter
Add the below dependency to your pom.xml:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.10.0.pr3</version>
</dependency>
Add the getter/setter missing inside the bean mentioned in the error message.
Use #ResponseBody and getter/setter. Hope it will solve your issue.
#RequestMapping(value = "/bar/foo", method = RequestMethod.GET)
#ResponseBody
public ResponseEntity<foo> foo() {
and update your mvc-dispatcher-servlet.xml:
<mvc:annotation-driven>
<mvc:message-converters>
<bean class="org.springframework.http.converter.StringHttpMessageConverter"/>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/>
</mvc:message-converters>
</mvc:annotation-driven>
The answer written by #Marc is also valid. But the concrete answer is the Getter method is required. You don't even need a Setter.
The issue occurred in my case because spring framework couldn't fetch the properties of nested objects. Getters/Setters is one way of solving. Making the properties public is another quick and dirty solution to validate if this is indeed the problem.
#EnableWebMvc annotation on config class resolved my problem. (Spring 5, no web.xml, initialized by AbstractAnnotationConfigDispatcherServletInitializer)
I had the very same problem, and unfortunately it could not be solved by adding getter methods, or adding jackson dependencies.
I then looked at Official Spring Guide, and followed their example as given here - https://spring.io/guides/gs/actuator-service/ - where the example also shows the conversion of returned object to JSON format.
I then again made my own project, with the difference that this time I also added the dependencies and build plugins that's present in the pom.xml file of the Official Spring Guide example I mentioned above.
The modified dependencies and build part of XML file looks like this!
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
You can see the same in the mentioned link above.
And magically, atleast for me, it works. So, if you have already exhausted your other options, you might want to try this out, as was the case with me.
Just a side note, it didn't work for me when I added the dependencies in my previous project and did Maven install and update project stuff. So, I had to again make my project from scratch. I didn't bother much about it as mine is an example project, but you might want to look for that too!
I was getting the same error for a while.I had verify getter methods were available for all properties.Still was getting the same error.
To resolve an issue Configure MVC xml(configuration) with
<mvc:annotation-driven/>
.This is required for Spring to detect the presence of jackson and setup the corresponding converters.
While using Spring Boot 2.2 I run into a similiar error message and while googling my error message
No converter for [class java.util.ArrayList] with preset Content-Type 'null'
this question here is on top, but all answers here did not work for me, so I think it's a good idea to add the answer I found myself:
I had to add the following dependencies to the pom.xml:
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-oxm</artifactId>
</dependency>
<dependency>
<groupId>com.thoughtworks.xstream</groupId>
<artifactId>xstream</artifactId>
<version>1.4.11.1</version>
</dependency>
After this I need to add the following to the WebApplication class:
#SpringBootApplication
public class WebApplication
{
// ...
#Bean
public HttpMessageConverter<Object> createXmlHttpMessageConverter()
{
final MarshallingHttpMessageConverter xmlConverter = new MarshallingHttpMessageConverter();
final XStreamMarshaller xstreamMarshaller = new XStreamMarshaller();
xstreamMarshaller.setAutodetectAnnotations(true);
xmlConverter.setMarshaller(xstreamMarshaller);
xmlConverter.setUnmarshaller(xstreamMarshaller);
return xmlConverter;
}
}
Last but not least within my #Controller I used:
#GetMapping(produces = {MediaType.APPLICATION_XML_VALUE, MediaType. APPLICATION_JSON_VALUE})
#ResponseBody
public List<MeterTypeEntity> listXmlJson(final Model model)
{
return this.service.list();
}
So now I got JSON and XML return values depending on the requests Accept header.
To make the XML output more readable (remove the complete package name from tag names) you could also add #XStreamAlias the following to your entity class:
#Table("ExampleTypes")
#XStreamAlias("ExampleType")
public class ExampleTypeEntity
{
// ...
}
Hopefully this will help others with the same problem.
In my case i'm using spring boot , and i have encountered a similar error :
No converter for [class java.util.ArrayList] with preset Content-Type 'null'
turns out that i have a controller with
#GetMapping(produces = { "application/xml", "application/json" })
and shamefully i wasn't adding the Accept header to my requests
you didn't have any getter/setter methods.
In my case, I was returning Boolean in Response Entity
and had :
produces = MediaType.TEXT_PLAIN_VALUE,
When i changed it to below
produces = MediaType.APPLICATION_JSON_VALUE
It worked!
Example of what i had.
#PostMapping(value = "/xxx-xxxx",
produces = MediaType.APPLICATION_JSON_VALUE,
consumes = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<Boolean> yyyy(
I was facing same issue for long time then comes to know have to convert object into JSON using Object Mapper and pass it as JSON Object
#RequestMapping(value = "/getTags", method = RequestMethod.GET)
public #ResponseBody String getTags(#RequestParam String tagName) throws
JsonGenerationException, JsonMappingException, IOException {
List<Tag> result = new ArrayList<Tag>();
for (Tag tag : data) {
if (tag.getTagName().contains(tagName)) {
result.add(tag);
}
}
ObjectMapper objectMapper = new ObjectMapper();
String json = objectMapper.writeValueAsString(result);
return json;
}
I also experienced such error when by accident put two #JsonProperty("some_value") identical lines on different properties inside the class
In my case, I forgot to add library jackson-core.jar, I only added jackson-annotations.jar and jackson-databind.jar. When I added jackson-core.jar, it fixed the problem.
I saw the same error when the scope of the jackson-databind dependency had been set to test:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.9</version>
<scope>test</scope>
</dependency>
Removing the <scope> line fixed the issue.
Faced same error recently - the pojo had getters/setters and all jackson dependencies were imported in pom correctly but some how "< scope > " was "provided" for jackson dependency and this caused the issue. Removing " < Scope > " from jackson dependency fixed the issue
I faced the same problem but I was using Lombok and my UploadFileResponse pojo was a builder.
public ResponseEntity<UploadFileResponse>
To solve I added #Getter annotation:
#Builder
#NoArgsConstructor
#AllArgsConstructor
#Getter
public class UploadFileResponse
Add below dependency in pom.xml:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>2.10.1</version>
</dependency>
Was facing the same issue as the return type cannot be bind with the MediaType of Class Foo. After adding the dependency it worked.
This might also happen due low Jackson version; e.g. Spring Boot 2.4 default Jackson version is too low when using Java records; you need at least 2.5 to serialize them properly.
I also encountered the same error on a Spring 5 project (not Spring Boot), by running a SpringMVC JUnit test-case on a method that returns ResponseEntity<List<MyPojo>>
Error: No converter found for return value of type: class java.util.ArrayList
I thought I had all the correct Jackson artifacts in my pom, but later realized that I had the legacy versions. The Maven groupId changed on the Jackson jars from org.codehaus.jacksonto com.fasterxml.jackson.core. After switching to the new jars the error went away.
Updated maven pom.xml:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.9.7</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.7</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>2.9.7</version>
</dependency>
You are missing an Annotation #ResponseBody

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