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 blog , we will learn in detail about How to build a Eureka server.

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 −

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 −

package com.tecklearn.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-eureka-server</artifactId>
</dependency>
The code for Gradle user dependency is given below −
compile(‘org.springframework.cloud:spring-cloud-starter-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
http://maven.apache.org/xsd/maven-4.0.0.xsd”>

<modelVersion>4.0.0</modelVersion>
<groupId>com.tecklearn</groupId>
<artifactId>eurekaserver</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>eurekaserver</name>
<description>Demo project for Spring Boot</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.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>
<spring-cloud.version>Edgware.RELEASE</spring-cloud.version>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-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 = '1.5.9.RELEASE'
}
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.tecklearn'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
mavenCentral()
}
ext {
springCloudVersion = 'Edgware.RELEASE'
}
dependencies {
compile('org.springframework.cloud:spring-cloud-starter-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
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 −

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 −

Service Registration with Eureka

In this chapter, you are going to learn in detail about How to register the Spring Boot Micro service application into the Eureka Server. Before registering the application, please make sure Eureka Server is running on the port 8761 or first build the Eureka Server and run it. For further information on building the Eureka server, you can refer to the previous chapter.
First, you need to add the following dependencies in our build configuration file to register the microservice with the Eureka server.
Maven users can add the following dependencies into the pom.xml file −
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
Gradle users can add the following dependencies into the build.gradle file −
compile(‘org.springframework.cloud:spring-cloud-starter-eureka’)
Now, we need to add the @EnableEurekaClient annotation in the main Spring Boot application class file. The @EnableEurekaClient annotation makes your Spring Boot application act as a Eureka client.
The main Spring Boot application is as given below −
package com.tecklearn.eurekaclient;

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

@SpringBootApplication
@EnableEurekaClient
public class EurekaclientApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaclientApplication.class, args);
}
}
To register the Spring Boot application into Eureka Server we need to add the following configuration in our application.properties file or application.yml file and specify the Eureka Server URL in our configuration.
The code for application.yml file is given below −
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka
instance:
preferIpAddress: true
spring:
application:
name: eurekaclient
The code for application.properties file is given below −
eureka.client.serviceUrl.defaultZone = http://localhost:8761/eureka
eureka.client.instance.preferIpAddress = true
spring.application.name = eurekaclient
Now, add the Rest Endpoint to return String in the main Spring Boot application and the Spring Boot Starter web dependency in build configuration file. Observe the code given below −
package com.tecklearn.eurekaclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@EnableEurekaClient
@RestController
public class EurekaclientApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaclientApplication.class, args);
}
@RequestMapping(value = “/”)
public String home() {
return “Eureka Client application”;
}
}
The entire configuration file is given below.
For Maven user – 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.tecklearn</groupId>
<artifactId>eurekaclient</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>eurekaclient</name>
<description>Demo project for Spring Boot</description>

<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</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>

</projecta>
For Gradle user – build.gradle
buildscript {
ext {
springBootVersion = ‘1.5.9.RELEASE’
}
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.tecklearn’
version = ‘0.0.1-SNAPSHOT’
sourceCompatibility = 1.8

repositories {
mavenCentral()
}
ext {
springCloudVersion = ‘Edgware.RELEASE’
}
dependencies {
compile(‘org.springframework.cloud:spring-cloud-starter-eureka’)
testCompile(‘org.springframework.boot:spring-boot-starter-test’)
compile(‘org.springframework.boot:spring-boot-starter-web’)
}
dependencyManagement {
imports {
mavenBom “org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}”
}
}
You can create an executable JAR file, and run the Spring Boot application by using the following Maven or Gradle commands −
For Maven, you can use the following command −
mvn clean install
After “BUILD SUCCESS”, you can find the JAR file under the target directory.
For Gradle, you can use the following command −
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 command as shown −
java –jar <JARFILE>
Now, the application has started on the Tomcat port 8080 and Eureka Client application is registered with the Eureka Server as shown below −

Hit the URL http://localhost:8761/ in your web browser and you can see the Eureka Client application is registered with Eureka Server.

Now hit the URL http://localhost:8080/ in your web browser and see the Rest Endpoint output.

So, this brings us to the end of blog. This Tecklearn ‘How to build a Eureka Server using Spring Boot’ blog helps you with commonly asked questions if you are looking out for a job in Java Programming. If you wish to learn Spring Boot and build a career Java Programming domain, then check out our interactive, Java and JEE Training, that comes with 24*7 support to guide you throughout your learning period. Please find the link for course details:

Java and JEE Training

Java and JEE Training

About the Course

Java and JEE Certification Training is designed by professionals as per the industrial requirements and demands. This training encompasses comprehensive knowledge on basic and advanced concepts of core Java & J2EE along with popular frameworks like Hibernate, Spring & SOA. In this course, you will gain expertise in concepts like Java Array, Java OOPs, Java Function, Java Loops, Java Collections, Java Thread, Java Servlet, and Web Services using industry use-cases and this will help you to become a certified Java expert.

Why Should you take Java and JEE Training?

• Java developers are in great demand in the job market. With average pay going between $90,000/- to $120,000/- depending on your experience and the employers.
• Used by more than 10 Million developers worldwide to develop applications for 15 Billion devices.
• Java is one of the most popular programming languages in the software world. Rated #1 in TIOBE Popular programming languages index (15th Consecutive Year)

What you will Learn in this Course?

Introduction to Java
• Java Fundamentals
• Introduction to Java Basics
• Features of Java
• Various components of Java language
• Benefits of Java over other programming languages
• Key Benefits of Java
Installation and IDE’s for Java Programming Language
• Installation of Java
• Setting up of Eclipse IDE
• Components of Java Program
• Editors and IDEs used for Java Programming
• Writing a Simple Java Program
Data Handling and Functions
• Data types, Operations, Compilation process, Class files, Loops, Conditions
• Using Loop Constructs
• Arrays- Single Dimensional and Multi-Dimensional
• Functions
• Functions with Arguments
OOPS in Java: Concept of Object Orientation
• Object Oriented Programming in Java
• Implement classes and objects in Java
• Create Class Constructors
• Overload Constructors
• Inheritance
• Inherit Classes and create sub-classes
• Implement abstract classes and methods
• Use static keyword
• Implement Interfaces and use it
Polymorphism, Packages and String Handling
• Concept of Static and Run time Polymorphism
• Function Overloading
• String Handling –String Class
• Java Packages
Exception Handling and Multi-Threading
• Exception handling
• Various Types of Exception Handling
• Introduction to multi-threading in Java
• Extending the thread class
• Synchronizing the thread
File Handling in Java
• Input Output Streams
• Java.io Package
• File Handling in Java
Java Collections
• Wrapper Classes and Inner Classes: Integer, Character, Boolean, Float etc
• Applet Programs: How to write UI programs with Applet, Java.lang, Java.io, Java.util
• Collections: ArrayList, Vector, HashSet, TreeSet, HashMap, HashTable
Java Database Connectivity (JDBC)
• Introduction to SQL: Connect, Insert, Update, Delete, Select
• Introduction to JDBC and Architecture of JDBC
• Insert/Update/Delete/Select Operations using JDBC
• Batch Processing Transaction
• Management: Commit and Rollback
Java Enterprise Edition – Servlets
• Introduction to J2EE
• Client Server architecture
• URL, Port Number, Request, Response
• Need for servlets
• Servlet fundamentals
• Setting up a web project in Eclipse
• Configuring and running the web app with servlets
• GET and POST request in web application with demo
• Servlet lifecycle
• Servlets Continued
• Session tracking and filter
• Forward and include Servlet request dispatchers
Java Server Pages (JSP)
• Fundamentals of Java Server Page
• Writing a code using JSP
• The architecture of JSP
• JSP Continued
• JSP elements: Scriptlets, expressions, declaration
• JSP standard actions
• JSP directives
• Introduction to JavaBeans
• ServletConfig and ServletContext
• Servlet Chaining
• Cookies Management
• Session Management
Hibernate
• Introduction to Hibernate
• Introduction to ORM
• ORM features
• Hibernate as an ORM framework
• Hibernate features
• Setting up a project with Hibernate framework
• Basic APIs needed to do CRUD operations with Hibernate
• Hibernate Architecture
POJO (Plain Old Java Object)
• POJO (Plain Old Java Object)
• Persistent Objects
• Lifecycle of Persistent Object
Spring
• Introduction to Spring
• Spring Fundamentals
• Advanced Spring
Got a question for us? Please mention it in the comments section and we will get back to you.

406