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Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication at com.javacourse.springBootDemo

I am taking that mistake but I am working to solve the mistake , really I do not know why I am taking error ? In stackoverflow , there is similar of my error . I tried these but it did not work again. I used java 1.8 jdk and spring boot 2.3.2
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>2.3.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.javakerem</groupId>
<artifactId>SpringBootDemoo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>SpringBootDemoo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.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-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
SpringBootDemooApplication.java
package com.javakerem.SpringBootDemoo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class SpringBootDemooApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBootDemooApplication.class, args);
}
}
ProductsController.java
package com.javakerem.SpringBootDemoo.apiTest;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
#RestController
public class ProductsController {
#GetMapping("/")
public String get()
{
return "Kerem Kagan";
}
}
I can write a little english , i am sorry if i wrote false.
Mistake is that :
Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication
at com.javacourse.springBootDemo.SpringBootDemoApplication.main(SpringBootDemoApplication.java:10)
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
... 1 more

cd to THE_PROJECT_FOLDER via the cmd or git bash
mvn clean
maven install
maven package
go to the project using your IDE and go to the class containing the main method
Click on the #SpringBootApplication and see to the left an icon like a lamp
Click on it and select download with maven
run the applcation
Try this it may work fine for you

Ektorp dependency crashing Spring boot application

I`m making a web application. The back-end is in Java, and I use Spring. For the database I use CouchDb and I want to use Ektorp, but here comes the problem. It crashes when I add the Ektorp dependency. It compiles, but when I try to run, I get the errors from below.
Exception in thread "main" java.lang.IllegalArgumentException: Cannot instantiate interface org.springframework.context.ApplicationListener : org.springframework.boot.context.logging.ClasspathLoggingApplicationListener
at org.springframework.boot.SpringApplication.createSpringFactoriesInstances(SpringApplication.java:450)
at org.springframework.boot.SpringApplication.getSpringFactoriesInstances(SpringApplication.java:429)
at org.springframework.boot.SpringApplication.getSpringFactoriesInstances(SpringApplication.java:420)
at org.springframework.boot.SpringApplication.<init>(SpringApplication.java:270)
at org.springframework.boot.SpringApplication.<init>(SpringApplication.java:249)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248)
at QEasyApplication.main(QEasyApplication.java:18)
Caused by: java.lang.NoClassDefFoundError: org/springframework/context/event/GenericApplicationListener
at java.base/java.lang.ClassLoader.defineClass1(Native Method)
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)
at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:174)
at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:802)
at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:700)
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:623)
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:398)
at org.springframework.util.ClassUtils.forName(ClassUtils.java:275)
at org.springframework.boot.SpringApplication.createSpringFactoriesInstances(SpringApplication.java:442)
... 7 more
Caused by: java.lang.ClassNotFoundException: org.springframework.context.event.GenericApplicationListener
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
... 20 more
Process finished with exit code 1
I tried changing to different versions of Ektorp or spring boot but nothing worked. Down below is my Maven pom file. What could be the problem?
<?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>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>2.1.3.RELEASE</version>
<type>pom</type>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>2.1.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
<version>2.1.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
<version>2.1.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.ektorp</groupId>
<artifactId>org.ektorp.spring</artifactId>
<version>1.4.4</version>
</dependency>
</dependencies>
</project>

Well it seems that org.springframework.context.event.GenericApplicationListener is not on your classpath. It resides in spring-context.
You state, in other words your pom.xml states, that someone should provide spring-boot-dependencies for you? I think you confused the provided and the import Maven scopes:
provided – "you expect the JDK or a container to provide the dependency at runtime"
import – "It indicates the dependency to be replaced with the effective list of dependencies in the specified POM's section."
So two possibilities:
switch the runtime scope of spring-boot-dependencies to import
even better, let Spring Boot manage as many dependencies as possible for you and put the following parent pom in place, to leverage the full potential of Spring Boot:
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.RELEASE</version>
</parent>

Spring boot app with Netfilx Eureka fails to start after being packaged into a fat jar

So I have been following this Microservices with Spring Boot guide and everything seems to work as expected in the IDE(intelliJ IDEA), the Eureka Server starts and functions as expected.
However, a problem occured after I exported my Eureka server as a fat jar.
To package the Eureka server into a fat jar I used mvn clean package in the terminal which has always worked for me.
After that when I tried to run the jar using java -jar myjar.jar I got the following exception
org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:155) ~[spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-5.0.4.RELEASE.jar!/:5.0.4.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752) [spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:388) [spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246) [spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234) [spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.tushinov.ServiceRegistryStarter.main(ServiceRegistryStarter.java:11) [classes!/:1.0]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Unknown Source) ~[na:na]
at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) [service-registry-1.0.jar:1.0]
at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) [service-registry-1.0.jar:1.0]
at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) [service-registry-1.0.jar:1.0]
at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) [service-registry-1.0.jar:1.0]
Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:125) ~[spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:86) ~[spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:417) ~[spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:176) ~[spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:179) ~[spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:152) ~[spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
... 16 common frames omitted
Caused by: java.lang.IllegalStateException: StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[] failed to start
at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.rethrowDeferredStartupExceptions(TomcatWebServer.java:171) ~[spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:110) ~[spring-boot-2.0.0.RELEASE.jar!/:2.0.0.RELEASE]
... 21 common frames omitted
After looking around in Stackoverflow I came across this question but it did not manage to help me with the problem. So I decided to ask a question myself.
I have used mvn clean package for making fat jars for quite some time and never had an issue. How come this time it fails? Im guessing it has something to do with the netflix eureka server. Maybe a missing configuration or something similar.
So here is everything that I currently have:
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>org.tushinov</groupId>
<artifactId>service-registry</artifactId>
<version>1.0</version>
<packaging>jar</packaging>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.0.RELEASE</version>
<relativePath/>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-netflix-eureka-server -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
<version>2.0.0.RELEASE</version>
</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>
application.properties
spring.application.name=eureka-server
server.port=8761
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
and the code
package org.tushinov;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
#SpringBootApplication
#EnableEurekaServer
public class ServiceRegistryStarter {
public static void main(String[] args) {
SpringApplication.run(ServiceRegistryStarter.class, args);
}
}
If I have missed anything please ask away in the comments for clarification.
Any help and/or suggestion are welcome and greatly appreciated!

After some time I found the answer to this problem. It was not a configuration or anything like it. It was a JDK mistmatch in intelliJ and maven. In intelliJ I was using JDK 1.8 to compile and run my application.
The thing I did not realise was that mvn uses the JAVA_HOME parameter to find which JDK it is supposed to use as opposed to intelliJ where you can specify your jdk. The JAVA_HOME parameter in my case was pointing to JDK 1.9, which, apperantly, might need more dependencies and/or configuration in order to run the Netflix Eureka server.
These resources helped me with solving the problem.

Here is pom which works for me
<?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.microservices</groupId>
<artifactId>naming-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>naming-server</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.1.RELEASE</version>
<relativePath/>
</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>Finchley.M9</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</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>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
</project>

spring boot app - beanUtils not found

In eclipse I create a new spring boot starter project. The Spring Boot Version is 1.5.9.RELEASE and the dependency I include is the spring-boot-starter-web (this is all done by the Spring Project wizard in eclipse, so likely no error there). When I run it as Spring Boot app, I get the error
Exception in thread "main" java.lang.IllegalArgumentException: Cannot instantiate interface org.springframework.context.ApplicationContextInitializer : org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer
at org.springframework.boot.SpringApplication.createSpringFactoriesInstances(SpringApplication.java:413)
at org.springframework.boot.SpringApplication.getSpringFactoriesInstances(SpringApplication.java:392)
at org.springframework.boot.SpringApplication.getSpringFactoriesInstances(SpringApplication.java:383)
at org.springframework.boot.SpringApplication.initialize(SpringApplication.java:249)
at org.springframework.boot.SpringApplication.<init>(SpringApplication.java:225)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107)
at spring.demo.rest.DemoApplication.main(DemoApplication.java:10)
Caused by: java.lang.NoClassDefFoundError: org/springframework/beans/BeanUtils
at org.springframework.boot.SpringApplication.createSpringFactoriesInstances(SpringApplication.java:409)
... 7 more
Caused by: java.lang.ClassNotFoundException: org.springframework.beans.BeanUtils
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 8 more
The class BeanUtils is in the spring-beans library which is clearly imported
This is my pom
<?xml version="1.0" encoding="UTF-8"?>
http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
<groupId>spring.demo.rest</groupId>
<artifactId>restdemo</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>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>
</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-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
Note: I am behind a corporate proxy and the nexus we have mirrors the maven central repo. I have setup the proxy in settings.xml
EDIT
What I noticed was that the spring-beans4.3.13.RELEASE.jar is installed to org/springframeword/spring-beans/4.3.13.RELEASE but the app looks for BeanUtils in org/springframework/beans/BeanUtils. There must be some version incompatability right?

ClassNotFoundException while running a Spring Boot application

I am new to Spring boot.I am getting ClassNotFoundException :Spring Application while doing the sample example using spring 1.5.7. I googled for solution and added spring boot maven build plugin.But still the problem not resolved. Please help.
<?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>1.5.7.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-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>
</project>
Below is my main class
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
I am getting the below Exception :
Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication
at com.example.demo.DemoApplication.main(DemoApplication.java:10)
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 1 more

The best way to create a spring boot project from scratch irrespective of build tool (maven, gradle, etc..) is to use https://start.spring.io/ search for your dependencies like (Web, actuator, etc..) and generate the project. Unzip the downloaded project and type the respective command mvn spring-boot:run in your case.

It seems to me that relevant dependencies are not downloaded from maven repo.
Try following command and check if the package compiles okay!
./mvnw clean package