Vaadin & Spring Boot 2.0.4 throwing java.lang.ClassNotFoundException: eleme

I am getting an exception with Spring Boot latest and Vaadin.
Tried to understand and debug what can be wrong (Jar hells, different versions etc), but nothing.
Here is the stack:

java.lang.ClassNotFoundException: elemental.json.JsonException
	at java.net.URLClassLoader.findClass(Unknown Source) ~[na:1.8.0_171]

	at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_171]

	at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) ~[na:1.8.0_171]

	at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_171]

	at com.vaadin.flow.spring.SpringServlet.createServletService(SpringServlet.java:54) ~[vaadin-spring-10.0.3.jar:na]

	at com.vaadin.flow.server.VaadinServlet.createServletService(VaadinServlet.java:240) ~[flow-server-1.0.4.jar:na]

	at com.vaadin.flow.server.VaadinServlet.init(VaadinServlet.java:77) ~[flow-server-1.0.4.jar:na]

My view class:

package com.example.demo;

import com.vaadin.flow.component.button.Button;
import com.vaadin.flow.component.notification.Notification;
import com.vaadin.flow.component.orderedlayout.VerticalLayout;
import com.vaadin.flow.router.Route;

@Route("vaadin")
public class MainView extends VerticalLayout {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public MainView() {
		add(new Button("Click me", e -> Notification.show("Hello Spring+Vaadin user!")));
	}

}

My dependency config is quite simple as you can see:

<?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>demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>demo</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>
		<vaadin.version>10.0.4</vaadin.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-web-services</artifactId>
		</dependency>
		<dependency>
			<groupId>com.vaadin</groupId>
			<artifactId>vaadin-spring-boot-starter</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>com.vaadin</groupId>
				<artifactId>vaadin-bom</artifactId>
				<version>${vaadin.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>

and my environment info:

java version "1.8.0_171"
Java(TM) SE Runtime Environment (build 1.8.0_171-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.171-b11, mixed mode)

Apache Maven 3.5.2 (138edd61fd100ec658bfa2d307c43b76940a5d7d; 2017-10-18T10:58:13+03:00)
Maven home: C:\Users\Sigmar\Apps\apache-maven-3.5.2\bin\..
Java version: 1.8.0_144, vendor: Oracle Corporation
Java home: C:\Program Files\Java\jdk1.8.0_144\jre
Default locale: en_US, platform encoding: Cp1257
OS name: "windows 10", version: "10.0", arch: "amd64", family: "windows"

I tried with some test code like this:

	public static void main(String[] args) {
		Class cls = elemental.json.JsonValue.class;
		System.out.println(cls);
	}

And still got the same error. Any class from the “elemental” package cannot be found.

I checked my classpath and yes, the GWT Elemental Jar is there. But as its very old, then there seems to be some issue with it. I am suspecting that this combo does not work with Java 8. Anyone else with the same problem?

17249638.zip (57.5 KB)

I tested our Bakery (see vaadin.com/start ) Vaadin 10 app with same Spring Boot 2.0.4 version as you have, and it works totally ok. Also, it works with Java 8. So I suspect that you have corrupt jars or something that causes this problem. Clearing those from .m2 cache and letting maven to download them again could help.