title: Pass, return and convert to vectors list of lists over JNI
body: <p>I need to pass from Java</p>
  
  <pre><code>List&lt; List&lt;MyPoint&gt; &gt; points;
  </code></pre>
  
  <p>over jni to C++ and convert to </p>
  
  <pre><code>std::vector&lt; std::vector&lt;MyPoint&gt; &gt;
  </code></pre>
  
  <p>Process this vectors and return </p>
  
  <pre><code>List&lt; List&lt;MyPoint&gt; &gt;
  </code></pre>
  
  <ol>
  <li>How correct pass and return list of lists?</li>
  <li>How convert list of lists of objects in vector of vectors of objects and backward?</li>
  </ol>