title: Diamond type are not supported at this language level
body: <p>After importing a project into Android studio, if I want to compile or run the project it throws an error:</p>
  
  <blockquote>
    <p>Error:(61, 65) java: diamond operator is not supported in -source 1.6<br>
    (use -source 7 or higher to enable diamond operator)</p>
  </blockquote>
  
  <p>Does anyone know what it is and how to solve it ?</p>