title: Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication at com.javacourse.springBootDemo
body: <p>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</p>
  <p>pom.xml</p>
  <pre><code>    &lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
  &lt;project xmlns=&quot;http://maven.apache.org/POM/4.0.0&quot; xmlns:xsi=&quot;http://www.w3.org/2001/XMLSchema-instance&quot;
      xsi:schemaLocation=&quot;http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd&quot;&gt;
      &lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
      &lt;parent&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-parent&lt;/artifactId&gt;
          &lt;version&gt;2.3.2.RELEASE&lt;/version&gt;
          &lt;relativePath/&gt; &lt;!-- lookup parent from repository --&gt;
      &lt;/parent&gt;
      &lt;groupId&gt;com.javakerem&lt;/groupId&gt;
      &lt;artifactId&gt;SpringBootDemoo&lt;/artifactId&gt;
      &lt;version&gt;0.0.1-SNAPSHOT&lt;/version&gt;
      &lt;name&gt;SpringBootDemoo&lt;/name&gt;
      &lt;description&gt;Demo project for Spring Boot&lt;/description&gt;
  
      &lt;properties&gt;
          &lt;java.version&gt;1.8&lt;/java.version&gt;
      &lt;/properties&gt;
  
      &lt;dependencies&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
              &lt;artifactId&gt;spring-boot-starter-web&lt;/artifactId&gt;
          &lt;/dependency&gt;
  
          &lt;dependency&gt;
              &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
              &lt;artifactId&gt;spring-boot-starter-test&lt;/artifactId&gt;
              &lt;scope&gt;test&lt;/scope&gt;
              &lt;exclusions&gt;
                  &lt;exclusion&gt;
                      &lt;groupId&gt;org.junit.vintage&lt;/groupId&gt;
                      &lt;artifactId&gt;junit-vintage-engine&lt;/artifactId&gt;
                  &lt;/exclusion&gt;
              &lt;/exclusions&gt;
          &lt;/dependency&gt;
      &lt;/dependencies&gt;
  
      &lt;build&gt;
          &lt;plugins&gt;
              &lt;plugin&gt;
                  &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
                  &lt;artifactId&gt;spring-boot-maven-plugin&lt;/artifactId&gt;
              &lt;/plugin&gt;
          &lt;/plugins&gt;
      &lt;/build&gt;
  
  &lt;/project&gt;
  </code></pre>
  <p>SpringBootDemooApplication.java</p>
  <pre><code>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);
      }
  
  }
  </code></pre>
  <p>ProductsController.java</p>
  <pre><code>package com.javakerem.SpringBootDemoo.apiTest;
  import org.springframework.web.bind.annotation.GetMapping;
  import org.springframework.web.bind.annotation.RestController;
  
  @RestController
  public class ProductsController {
      
      @GetMapping(&quot;/&quot;)
      public String get()
      {
          return &quot;Kerem Kagan&quot;;
      }
      
  }   
  </code></pre>
  <p>I can write a little english , i am sorry if i wrote false.</p>
  <p>Mistake is that :</p>
  <pre><code>Exception in thread &quot;main&quot; 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
  </code></pre>