title: Maven Project on Eclipse revert java compiler version (from 1.8 to 1.5) after update (alt f5)
body: <p>as mentioned in the title I have this problem:
  if I try to edit the compiler version of my Maven Project (by right click on the proj -> Preferences -> Compiler...apply,ok ), <strong>after</strong> I press <strong>alt-f5</strong> (update) i loose all the previous settings and if i re-enter preferences menu i find the java compiler back to 1.5 (always JDK 8 , but 1.5 instead of 1.8).</p>
  
  <p>I tried many ways and combinations, e.g. setting compiler by Preferences -> Facet , or adding maven plugin to my pom, i really can't find a working solution.</p>
  
  <p><strong>Note that in my global preferences Java Runtime Enviroment is correctly set to JDK 8 1.8.</strong></p>
  
  <p>Anyone could help me? 
  Thanks in advance,</p>
  
  <p>Giulio</p>