title: Spring Tool Suite: @Configuration class may not be final. Remove the final modifier to continue
body: <p>I am unable to launch my spring boot kotlin app, due to the following:</p>
  
  <pre><code>org.springframework.beans.factory.parsing.BeanDefinitionParsingException: Configuration problem: @Configuration class 'TestApplication' may not be final. Remove the final modifier to continue.
  </code></pre>
  
  <p>I know that @configuration and @bean classes cannot be final so I add the allopen plugin in my pom file: </p>
  
  <pre><code>&lt;build&gt;
      &lt;sourceDirectory&gt;${project.basedir}/src/main/kotlin&lt;/sourceDirectory&gt;
      &lt;testSourceDirectory&gt;${project.basedir}/src/test/kotlin&lt;/testSourceDirectory&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;plugin&gt;
              &lt;groupId&gt;org.jetbrains.kotlin&lt;/groupId&gt;
              &lt;artifactId&gt;kotlin-maven-plugin&lt;/artifactId&gt;
              &lt;configuration&gt;
                  &lt;args&gt;
                      &lt;arg&gt;-Xjsr305=strict&lt;/arg&gt;
                  &lt;/args&gt;
                  &lt;compilerPlugins&gt;
                      &lt;plugin&gt;spring&lt;/plugin&gt;
                  &lt;/compilerPlugins&gt;
              &lt;/configuration&gt;
              &lt;dependencies&gt;
                  &lt;dependency&gt;
                      &lt;groupId&gt;org.jetbrains.kotlin&lt;/groupId&gt;
                      &lt;artifactId&gt;kotlin-maven-allopen&lt;/artifactId&gt;
                      &lt;version&gt;${kotlin.version}&lt;/version&gt;
                  &lt;/dependency&gt;
              &lt;/dependencies&gt;
          &lt;/plugin&gt;
      &lt;/plugins&gt;
  &lt;/build&gt;
  </code></pre>
  
  <p>If I package my application and run it (java -jar) it works, but when I try to launch it from STS it won't work. </p>
  
  <p>Kotlin version: 1.2.71
  Kotlin eclipse plugin: 0.8.13
  STS: 3.9.5</p>