Spring Boot Resources

Spring Boot - Eureka Server

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Eureka Server is an application that holds the information about all client-service applications. Every Micro service will register into the Eureka server and Eureka server knows all the client applications running on each port and IP address. Eureka Server is also known as Discovery Server.

In this chapter, we will learn in detail about How to build a Eureka server.

Example - Building a Eureka Server

Eureka Server comes with the bundle of Spring Cloud. For this, we need to develop the Eureka server and run it on the default port 8761.

Visit the Spring Initializer homepage https://start.spring.io/ and download the Spring Boot project with Eureka server dependency. It is shown in the screenshot below −

Build Eureka Server

After downloading the project in main Spring Boot Application class file, we need to add @EnableEurekaServer annotation. The @EnableEurekaServer annotation is used to make your Spring Boot application acts as a Eureka Server.

The code for main Spring Boot application class file is as shown below −

EurekaserverApplication.java

package com.tutorialspoint.eurekaserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class EurekaserverApplication {
   public static void main(String[] args) {
      SpringApplication.run(EurekaserverApplication.class, args);
   }
}

Make sure Spring cloud Eureka server dependency is added in your build configuration file.

The code for Maven user dependency is shown below −

<dependency>
<groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>

The code for Gradle user dependency is given below −

compile('org.springframework.cloud:spring-cloud-starter-netflix-eureka-server')

The complete build configuration file is given below −

Maven - 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>3.5.6</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.tutorialspoint</groupId>
   <artifactId>eurekaserver</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>eurekaserver</name>
   <description>Demo project for Spring Boot</description>
   <url/>
   <licenses>
      <license/>
   </licenses>
   <developers>
      <developer/>
   </developers>
   <scm>
      <connection/>
      <developerConnection/>
      <tag/>
      <url/>
   </scm>
   <properties>
      <java.version>21</java.version>
      <spring-cloud.version>2025.0.0</spring-cloud.version>
   </properties>
   <dependencies>
      <dependency>
         <groupId>org.springframework.cloud</groupId>
         <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
   </dependencies>
   <dependencyManagement>
      <dependencies>
         <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
         </dependency>
      </dependencies>
   </dependencyManagement>
   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
         </plugin>
      </plugins>
   </build>
</project>

Gradle build.gradle

buildscript {
   ext {
      springBootVersion = '3.5.6'
   }
   repositories {
      mavenCentral()
   }
   dependencies {
      classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
   }
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'

group = 'com.tutorialspoint'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 21

repositories {
   mavenCentral()
}
ext {
   springCloudVersion = '2025.0.0'
}
dependencies {
   compile('org.springframework.cloud:spring-cloud-starter-netflix-eureka-server')
   testCompile('org.springframework.boot:spring-boot-starter-test')
}
dependencyManagement {
   imports {
      mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
   }
}

By default, the Eureka Server registers itself into the discovery. You should add the below given configuration into your application.properties file or application.yml file.

application.properties file is given below −

eureka.client.registerWithEureka = false
eureka.client.fetchRegistry = false
server.port = 8761

The application.yml file is given below −

eureka:
   client:
      registerWithEureka: false
      fetchRegistry: false
server:
   port: 8761

Output

Now, you can create an executable JAR file, and run the Spring Boot application by using the Maven or Gradle commands shown below −

For Maven, use the command as shown below −

mvn clean install

After "BUILD SUCCESS", you can find the JAR file under the target directory.

For Gradle, you can use the command shown below −

gradle clean build

After "BUILD SUCCESSFUL", you can find the JAR file under the build/libs directory.

Now, run the JAR file by using the following command −

 java jar <JARFILE>

You can find that the application has started on the Tomcat port 8761 as shown below −

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/

 :: Spring Boot ::                (v3.5.6)

2025-09-29T12:45:26.399+05:30  INFO 41552 --- [eurekaserver] [           main] c.t.e.EurekaserverApplication            : Starting EurekaserverApplication using Java 21.0.6 with PID 41552 (D:\Projects\eurekaserver\target\classes started by mahes in D:\Projects\eurekaserver)
2025-09-29T12:45:26.402+05:30  INFO 41552 --- [eurekaserver] [           main] c.t.e.EurekaserverApplication            : No active profile set, falling back to 1 default profile: "default"
2025-09-29T12:45:27.714+05:30  INFO 41552 --- [eurekaserver] [           main] o.s.cloud.context.scope.GenericScope     : BeanFactory id=37b0aecd-4feb-3fa0-b028-b62a23271b1d
2025-09-29T12:45:28.120+05:30  INFO 41552 --- [eurekaserver] [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port 8761 (http)
2025-09-29T12:45:28.160+05:30  INFO 41552 --- [eurekaserver] [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2025-09-29T12:45:28.160+05:30  INFO 41552 --- [eurekaserver] [           main] o.apache.catalina.core.StandardEngine    : Starting Servlet engine: [Apache Tomcat/10.1.46]
2025-09-29T12:45:28.243+05:30  INFO 41552 --- [eurekaserver] [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2025-09-29T12:45:28.246+05:30  INFO 41552 --- [eurekaserver] [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1783 ms
2025-09-29T12:45:29.129+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.d.provider.DiscoveryJerseyProvider   : Using JSON encoding codec LegacyJacksonJson
2025-09-29T12:45:29.130+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.d.provider.DiscoveryJerseyProvider   : Using JSON decoding codec LegacyJacksonJson
2025-09-29T12:45:29.316+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.d.provider.DiscoveryJerseyProvider   : Using XML encoding codec XStreamXml
2025-09-29T12:45:29.317+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.d.provider.DiscoveryJerseyProvider   : Using XML decoding codec XStreamXml
2025-09-29T12:45:29.532+05:30  INFO 41552 --- [eurekaserver] [           main] o.s.v.b.OptionalValidatorFactoryBean     : Failed to set up a Bean Validation provider: jakarta.validation.NoProviderFoundException: Unable to create a Configuration, because no Jakarta Bean Validation provider could be found. Add a provider like Hibernate Validator (RI) to your classpath.
2025-09-29T12:45:30.289+05:30  WARN 41552 --- [eurekaserver] [           main] iguration$LoadBalancerCaffeineWarnLogger : Spring Cloud LoadBalancer is currently working with the default cache. While this cache implementation is useful for development and tests, it's recommended to use Caffeine cache in production.You can switch to using Caffeine cache, by adding it and org.springframework.cache.caffeine.CaffeineCacheManager to the classpath.
2025-09-29T12:45:30.318+05:30  INFO 41552 --- [eurekaserver] [           main] o.s.c.n.eureka.InstanceInfoFactory       : Setting initial instance status as: STARTING
2025-09-29T12:45:30.344+05:30  INFO 41552 --- [eurekaserver] [           main] com.netflix.discovery.DiscoveryClient    : Initializing Eureka in region us-east-1
2025-09-29T12:45:30.345+05:30  INFO 41552 --- [eurekaserver] [           main] com.netflix.discovery.DiscoveryClient    : Client configured to neither register nor query for data.
2025-09-29T12:45:30.348+05:30  INFO 41552 --- [eurekaserver] [           main] com.netflix.discovery.DiscoveryClient    : Discovery Client initialized at timestamp 1759130130346 with initial instances count: 0
2025-09-29T12:45:30.401+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.eureka.DefaultEurekaServerContext    : Initializing ...
2025-09-29T12:45:30.403+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.eureka.cluster.PeerEurekaNodes       : Adding new peer nodes [http://localhost:8761/eureka/]
2025-09-29T12:45:30.524+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.d.provider.DiscoveryJerseyProvider   : Using JSON encoding codec LegacyJacksonJson
2025-09-29T12:45:30.524+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.d.provider.DiscoveryJerseyProvider   : Using JSON decoding codec LegacyJacksonJson
2025-09-29T12:45:30.524+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.d.provider.DiscoveryJerseyProvider   : Using XML encoding codec XStreamXml
2025-09-29T12:45:30.524+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.d.provider.DiscoveryJerseyProvider   : Using XML decoding codec XStreamXml
2025-09-29T12:45:30.579+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.eureka.cluster.PeerEurekaNodes       : Replica node URL:  http://localhost:8761/eureka/
2025-09-29T12:45:30.589+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.e.registry.AbstractInstanceRegistry  : Finished initializing remote region registries. All known remote regions: []
2025-09-29T12:45:30.589+05:30  INFO 41552 --- [eurekaserver] [           main] c.n.eureka.DefaultEurekaServerContext    : Initialized
2025-09-29T12:45:30.608+05:30  INFO 41552 --- [eurekaserver] [           main] o.s.b.a.e.web.EndpointLinksResolver      : Exposing 1 endpoint beneath base path '/actuator'
2025-09-29T12:45:30.675+05:30  INFO 41552 --- [eurekaserver] [           main] o.s.c.n.e.s.EurekaServiceRegistry        : Registering application EUREKASERVER with eureka with status UP
2025-09-29T12:45:30.688+05:30  INFO 41552 --- [eurekaserver] [       Thread-9] o.s.c.n.e.server.EurekaServerBootstrap   : isAws returned false
2025-09-29T12:45:30.688+05:30  INFO 41552 --- [eurekaserver] [       Thread-9] o.s.c.n.e.server.EurekaServerBootstrap   : Initialized server context
2025-09-29T12:45:30.688+05:30  INFO 41552 --- [eurekaserver] [       Thread-9] c.n.e.r.PeerAwareInstanceRegistryImpl    : Got 1 instances from neighboring DS node
2025-09-29T12:45:30.688+05:30  INFO 41552 --- [eurekaserver] [       Thread-9] c.n.e.r.PeerAwareInstanceRegistryImpl    : Renew threshold is: 1
2025-09-29T12:45:30.689+05:30  INFO 41552 --- [eurekaserver] [       Thread-9] c.n.e.r.PeerAwareInstanceRegistryImpl    : Changing status to UP
2025-09-29T12:45:30.692+05:30  INFO 41552 --- [eurekaserver] [       Thread-9] e.s.EurekaServerInitializerConfiguration : Started Eureka Server
2025-09-29T12:45:30.711+05:30  INFO 41552 --- [eurekaserver] [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port 8761 (http) with context path '/'
2025-09-29T12:45:30.712+05:30  INFO 41552 --- [eurekaserver] [           main] .s.c.n.e.s.EurekaAutoServiceRegistration : Updating port to 8761
2025-09-29T12:45:30.734+05:30  INFO 41552 --- [eurekaserver] [           main] c.t.e.EurekaserverApplication            : Started EurekaserverApplication in 4.802 seconds (process running for 5.424)

Now, hit the URL http://localhost:8761/ in your web browser and you can find the Eureka Server running on the port 8761 as shown below −

Eureka Server Running on port 8761
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