title: Android Studio can't find java compiler
body: <p>I downloaded a Android project and wanted to try it. So I imported it to Android Studio (2.2) and when running the project i get the error:</p>
  
  <blockquote>
    <p>Error:Execution failed for task ':app:compileDebugJava'.
    Cannot find System Java Compiler. Ensure that you have installed a JDK (not just a JRE) and configured your JAVA_HOME system variable to point to the according directory.</p>
  </blockquote>
  
  <p>Before the runnning of every project worked and i'm searching for days but still found no working solution.</p>
  
  <p>EDIT: Here is my project structure:
  <a href="https://i.stack.imgur.com/dL06v.png" rel="noreferrer">project structure</a></p>
  
  <p>Maybe someone of you has the solution.</p>