title: Show "java.lang.NoClassDefFoundError" (with Maven) when using "Code Runner"
body: <p>I am using VSCode with Maven to learn Java(my javac -version is 11.0.10) under macOS Big Sur.</p>
  <p>It is ok when I run the code in the terminal by using &quot;RUN,&quot; which show on the list of VSCode. However, it always shows the error &quot;Could Not Find Or Load Main Class&quot;(actually in Chinese &quot;找不到或無法載入主要類別 hello&quot;) and the reason &quot;java.lang.NoClassDefFoundError: org/seifert/learnjava8/hello (wrong name: hello)&quot;.</p>
  <p>As you can see, the .java file is just a straightforward one to show&quot;hello world.&quot;
  <a href="https://i.stack.imgur.com/eZxos.png" rel="nofollow noreferrer">the whole screen image here</a></p>
  <p>Had anyone who uses Code Runner met this problem before? How can I resolve this?</p>