title: Android library project cannot be launched?
body: <p>I am totally confused by this error message: <code>Android library projects cannot be launched.</code></p>
  
  <p>I carefully checked the <code>build path</code> and <code>library</code>, everything is <code>"OK"</code>. And there is no error in Problems view. However, when I tried to run my application as an Android project, it failed and showed this message.</p>
  
  <p>already i have set library in properties check. my build Path also all are fine. when run my application error message is coming.In my application i have added <code>Google play service library</code></p>
  
  <p>please tell me any suggestions. </p>