Errors when running SpringBoot Admin app

Question

I am trying to use Springboot admin app and am unable to get the basics working.

I started with the simplest springboot web app (using starter-web and starter-test) and added the springboot-admin-server and springboot-admin-server-ui to the list of dependencies.

<dependencies>
    <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>


    <!-- Added Dependency for Admin Server and its UI --> 
    <dependency>
        <groupId>de.codecentric</groupId>
        <artifactId>spring-boot-admin-server</artifactId>
        <version>1.4.5</version> 
    </dependency>
    <dependency>
        <groupId>de.codecentric</groupId>
        <artifactId>spring-boot-admin-server-ui</artifactId>
        <version>1.4.5</version> 
    </dependency>


</dependencies>

Trying to execute mvn clean package throws up errors. The root cause is shown below.

Caused by: java.lang.ClassNotFoundException: org.springframework.boot.context.embedded.ServletRegistrationBean
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_112]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_112]
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) ~[na:1.8.0_112]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_112]
    ... 51 common frames omitted

The springboot app has absolutely the barebones implementation (the addition of the EnableAdminServer annotation as shown below)

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import de.codecentric.boot.admin.config.EnableAdminServer;

    @SpringBootApplication
    @EnableAdminServer
    public class WorkingExampleSpringBootAdminApplication {

        public static void main(String[] args) {
            SpringApplication.run(WorkingExampleSpringBootAdminApplication.class, args);
        }
    }

I am guessing that this error occurs because this class (org.springframework.boot.context.embedded.ServletRegistrationBean) has been replaced with org.springframework.boot.web.servlet.ServletRegistrationBean (in 1.5.x)and this is likely used by the spring-boot-admin-server components.

I got around this issue by switching to an earlier version of Springboot (say 1.4.4). Is that the right thing to do? Or am I making any mistakes in my configuration?

Answer 1

Using the version 1.4.6 of spring-boot-admin-server and spring-boot-admin-server-ui instead of 1.4.5 fixes the issue.