title: How can I use AWS lambda layer by java (Layer is success in Lambda)...error is NoClassDefFoundError
body: <p>I built two project and added layers to AWS Lamba successfully.    </p>
  
  <p>And my functions use these two layers. </p>
  
  <p><strong>This is my structure of layer</strong></p>
  
  <p><img src="https://i.stack.imgur.com/A8e9f.png" alt="Screen shot"></p>
  
  <p>When I execute the function, an error happened: </p>
  
  <blockquote>
    <p>java.lang.NoClassDefFoundError</p>
  </blockquote>
  
  <p>I know the location of the layer is inside/opt, 
  but how can I use the layer's library in functions?</p>