title: Why I am getting `Proto class is is already defined in file`?
body: <p>The first proto file(main.proto) in <code>offline</code> directory</p>
  <pre><code>option java_package = &quot;com.xxx.proto&quot;;
  option java_outer_classname = &quot;Service1&quot;;
  option java_multiple_files = true;
  
  message Response {
      repeated Entity entity = 1;
  }
  
  message Entity {}
  </code></pre>
  <p>and here I have the second proto file(recent.proto) which is in recent</p>
  <pre><code>option java_package = &quot;com.xxx.proto&quot;;
  option java_outer_classname = &quot;Service2&quot;;
  option java_multiple_files = true;
  
  message Response {
      repeated Entity entity = 1;
      repeated Entity.Type type =2;
  }
  message Entity {}
  
  </code></pre>
  <p>And I receive <code>protoc: stdout: . stderr: offline/main.proto: &quot;offline.Response.entitiy&quot; is already defined in file &quot;recent/recent.proto&quot;.</code>
  Want to mention Entity are different for both cases, the class name is the same</p>