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Is there a way to know if there are more than one Spring Context in use?

I have 2 spring boot applications - an API service and a library.
library generates a non-executable, imporatable JAR, which is imported and used by API service. Here is the pom:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.6.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>library</artifactId>
<version>0.0.1</version>
<packaging>jar</packaging>
<name>library</name>
<description>Library Integration</description>
<properties>
<java.version>11</java.version>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<oauth2.version>2.1.1.RELEASE</oauth2.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.security.oauth.boot</groupId>
<artifactId>spring-security-oauth2-autoconfigure</artifactId>
<version>${oauth2.version}</version>
</dependency>
</dependencies>
</project>
Some other info about library project:
It does not have a class with main method i.e., no #SpringBootApplication
It has a Configuration class that scans components:
#Configuration
#ComponentScan("com.example.library")
public class LibraryConfiguration {}
In /resources/META-INF/spring.factories we read this configuration:
org.springframework.boot.autoconfigure.EnableAutoConfiguration=
com.example.library.LibraryConfiguration
This had to be done, as when we are importing library in API service project, API service is not able to find the classes which we want to use there. These classes are beans and hence need to be initialized.
For API service project, pom is like this:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.1.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>api-service</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>api service</name>
<description>api service</description>
<properties>
<java.version>11</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- JUnit -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<dependency>
<groupId>com.example</groupId>
<artifactId>library</artifactId>
<version>0.0.1</version>
</dependency>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
APIs of API service project use methods of library project. The project works fine, all the APIs work.
However, I would like to confirm that only one Spring context is in use and not 2. When API service is started, it has its own context. Then it gets library dependency, which might create its own context and initialise beans of library project.
Ideally, I would like that there is only one context and that is of API service project. Is there a way to ensure this?

I have created a similar Spring Boot Project few days back. This question didn't cross my mind ever. Reason being, How context get created and there can't be two Contexts.
You start your application by providing a main Class ( You can't provide two).
Application Context / BeanFactory are Spring managed Bean, Your Library is not different from any Spring boot dependency ( Spring MVC, Spring Security). In a single Application instance it will not create two different Contexts.
In Order to Verify. Write Below code in any Spring Managed Bean. If Spring boot comes up and doesn't give any Exception e.g. Multiple Beans of type ApplicationContext found. That will be a proof.
#Autowired
private ApplicationContext applicationContext;
Alternatively, Include a Actuator dependency and hit below URL . It will give you all beans created. Context is just a bean, Check if there are multiple Beans.
http://<address>:<management-port>/beans.

library does not create the context. However you can check it by Autowiring the ApplicationContext in your main boot class and printing the ID and display name for example :-
#Autowired
private ApplicationContext applicationContext;
System.out.println(applicationContext.getDisplayName());
System.out.println(applicationContext.getId());

There will not be two application context for your case since you don't have SpringBoot main class in library. In springboot application context is created when SpringApplication.run(this,args) is called.

Spring Boot Actuator Custom RestControllerEndpoint with RequestMapping Annotation on class level

I have some custom actuator endpoints which should have the same parameters after the endpoint id. Therefore I use the #RestEndpointController annotation to get "full" control over the endpoints via MVC annotations. But I recognized a problem when I use the #RequestMapping annotation on class level on my RestEndpointController class.
My sample implementation:
#Component
#RestControllerEndpoint(id = "tenant")
#RequestMapping("customer/{id}")
public class TenantEndpoint {
#GetMapping
public String getTenantById(#PathVariable("id") String customerId) {
return "Tenant_" + customerId;
}
}
with the following application.properties
management.endpoints.web.exposure.include=health, info, metrics, tenant
and my pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>11</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
when running this app, there are two endpoints registered in Spring Boot
/actuator/tenant/customer/{id}
/customer/{id}
How can I avoid the second (non actuator) endpoint to be registered?
Or is it a bug of Actuator / Spring-Boot?

Do not use #RequestMapping on class level. You can mention the subsequent path as part of #GetMapping. Below code will register only a single endpoint viz. /actuator/tenant/customer/{id}
#Component
#RestControllerEndpoint(id = "tenant")
public class TenantEndpoint {
#GetMapping("/customer/{id}")
public String getTenantById(#PathVariable("id") String customerId) {
return "Tenant_" + customerId;
}
}

you should try, I didn't check it, bring some feedback in case you test it please.
#Component
#RestControllerEndpoint(id = "tenant")
#RequestMapping("customer")
public class TenantEndpoint {
#GetMapping("/{id}")
public String getTenantById(#PathVariable("id") String customerId) {
return "Tenant_" + customerId;
}
}

Spring boot Field required a bean of type that could not be found

I'm going through the JPA starter tutorial for spring boot am struggling.
I know the question has been asked sometimes here ('Field required a bean of type that could not be found.' error spring restful API using mongodb)
But those problems are a bit different from what I have.
Structure
java
|
helloWorld
|
web/ -- HelloWorldController
Application
Customer
CustomerRepository
ServletInitializer
As you can see all my packages related to JPA are on the same level as my Application file . According to the tutorial (https://spring.io/guides/gs/accessing-data-jpa/) this should work
My Application class
package helloWorld;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
import org.springframework.context.annotation.ComponentScan;
#SpringBootApplication
public class Application extends SpringBootServletInitializer {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
#Autowired
CustomerRepository customerRepository;
#Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application.sources(Application.class);
}
}
CustomerRepository
package helloWorld;
import org.springframework.data.repository.CrudRepository;
import java.util.List;
public interface CustomerRepository extends CrudRepository<Customer, Long> {
List<Customer> findByLastName(String lastName);
}
When trying to use #Autowired I receive
***************************
APPLICATION FAILED TO START
***************************
Description:
Field customerRepository in helloWorld.Application required a bean of type 'helloWorld.CustomerRepository' that could not be found.
Action:
Consider defining a bean of type 'helloWorld.CustomerRepository' in your configuration.
Also, adding scanBasePackages={"helloWorld"}) to #SpringBootApplication does not help and from what I read it should also not be needed.
pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>helloWorld.com.example</groupId>
<artifactId>helloWorld</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<name>fireCommerce</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.4.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</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>
<plugin>
<groupId>com.microsoft.azure</groupId>
<artifactId>azure-webapp-maven-plugin</artifactId>
<version>1.1.0</version>
<configuration>
<resourceGroup>maven-projects</resourceGroup>
<appName>${project.artifactId}-${maven.build.timestamp}</appName>
<region>westus</region>
<javaVersion>1.8</javaVersion>
<deploymentType>war</deploymentType>
</configuration>
</plugin>
</plugins>
</build>
</project>
link to the github project

You are excluding the autoconfiguration of JPA repositories. Remove the line from application.properties to let Spring make CustomerRepository a bean and configure it.
spring.autoconfigure.exclude=org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration

In my case, I just forgot to add #Component to Impl class of interface!
These errors may be due to absence of one or more stereotype annotations.

I changed this Class Level Annotation from my Application Class.
From:
#SpringBootApplication(exclude = {DataSourceAutoConfiguration.class })
To:
#SpringBootApplication

Try Adding the #ComponentScan("package.path.to.your.repository") annotation above Application class.
- Just make sure your repository is in the the same package path that is written in #ComponentScan
#SpringBootApplication
#ComponentScan("helloworld")
public class Application extends SpringBootServletInitializer {
//your stuff
}

I had the same issue and everything was good except adding the below dependecies.
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-jpa</artifactId>
<version>2.4.2</version>
And, It worked for me

you need to add #Repository in repository

Unresolvable circular reference in SpringBoot

I am learning Spring Framework and now I am trying to make a simple Spring Boot application that would list all entries from a database (using Hibernate).
First I had a problem when SessionFactory would not be defined, but I managed to define it in Config Class. However, when I try to run the app now, I get the following error:
Description:
The dependencies of some of the beans in the application context form a cycle:
indexController (field private com.prvi.dao.CustomerDAO com.prvi.controllers.IndexController.customerDAO)
↓
customerDAOImpl (field private org.hibernate.SessionFactory com.prvi.dao.CustomerDAOImpl.sessionFactory)
┌─────┐
| sessionFactory defined in class path resource [com/prvi/ConfigPrvi.class]
└─────┘
Basically, I have IndexController, who gets GET / request, then it calls customerDAO to get list of customers and customerDAO uses sessionFactory to get Session and performs a query on DB. (I have omitted Service layer from the app for sake of simplicity)
Now, I have read that this error happens when a bean is dependent on a bean that is dependent on a first bean, making cyclical dependency. However, I do not understand where I made this cycle and how to fix it. Also, other answers on this topic have not provided me enough information to correct the error. They were mostly oversimplifies where cycle is clear, which is not the case here.
Here is what I have tried so far:
PrviApplication.java - entry point for Spring Boot
#SpringBootApplication
public class PrviApplication {
public static void main(String[] args) {
SpringApplication.run(PrviApplication.class, args);
}
}
ConfigPrvi.java - My Configuration file
#Configuration
#EnableAutoConfiguration
public class ConfigPrvi {
#Bean
public HibernateJpaSessionFactoryBean sessionFactory(EntityManagerFactory emf){
HibernateJpaSessionFactoryBean factory = new HibernateJpaSessionFactoryBean();
factory.setEntityManagerFactory(emf);
return factory;
}
}
IndexController.java - my Controller class, which handles GET /
#Controller
#RequestMapping("/")
public class IndexController {
#Autowired
private CustomerDAO customerDAO;
#GetMapping("/")
public String listCustomers(Model model){
model.addAttribute("customers", customerDAO.getAllCustomers());
return "index";
}
}
CustomerDAO.java - just an interface
public interface CustomerDAO {
public List<Customer> getAllCustomers();
}
CustomerDAOImpl.java - implementation, retrieves data from database
#Repository
public class CustomerDAOImpl implements CustomerDAO {
#Autowired
private SessionFactory sessionFactory;
#Transactional
public List<Customer> getAllCustomers(){
Session session = sessionFactory.getCurrentSession();
Query<Customer> query = session.createQuery("from Customer order by lastName", Customer.class);
List<Customer> customers = query.getResultList();
return customers;
}
}
Is it perhaps that cycle was made here:
main --> controller --> dao --> sessionFactory --> config --> main
If so, how can I rewrite the code so that I get rid of it?
EDIT: Added pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.prvi</groupId>
<artifactId>prvi</artifactId>
<version>0.0.1</version>
<packaging>jar</packaging>
<name>prvi</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.4.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.2.10.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>5.2.10.Final</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>

Issues with loading Multiple Application files in spring boot

I'm just started working on Spring Boot and having issues while running the spring boot application. SO scenario is - i have two project
One is called Parent Project SpringBoot and
Other project called web-app is maven module which added in Parent project as module.
In Both Projects(Parent and child) i have Application classes which load the context but somehow when i start the application it gives me some exceptions like on project SpringBoot: Unable to find a suitable main class, please add a mainClass property
On top of that when i run the web-app separately then it works but when i run it through Parent Project SpringBoot it throws me exceptions
Here is my code structure of Spring Boot Project (Parent Project)
Application.java
#Configuration
#ComponentScan
#EnableAutoConfiguration
#SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
Example.java
#RequestMapping("/api/**")
#RestController
public class Example {#RequestMapping(method = RequestMethod.GET, produces = {MediaType.APPLICATION_JSON_VALUE})
public String index() {
return "Hello World";
}
}
Pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>SpringBoot</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.2.1.RELEASE</version>
</parent>
<!-- Additional lines to be added here... -->
<modules>
<module>web-app</module>
</modules
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-mail</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
Second project which is web-app:
ApplicationWebApp.Java
#Configuration
#ComponentScan
#EnableAutoConfiguration
#SpringBootApplication
ApplicationWebApp
public class ApplicationWebApp {
public static void main(String[] args) {
SpringApplication.run(ApplicationWebApp.class, args);
}
}
Example.java
#RequestMapping("/apis/**")
#RestController
public class Example {#RequestMapping(method = RequestMethod.GET, produces = {MediaType.APPLICATION_JSON_VALUE})
public String index() {
return "Hello World";
}
}
Pom.xml
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.example</groupId>
<artifactId>SpringBoot</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<artifactId>web-app</artifactId>
</project>
I found couple of solutions on the stackoverflow and different forums by adding
<properties>
The main class to start by executing java -jar
<startclass>com.dashboard.backend.controllers.Application</startclass>
</properties>
By this way, i need to add this properly file in each n every pom.xml to load it. Since this is a web based application so I'm not sure whether its a good solution or not..
If anyone have tried any solution for this problem please share you findings