title: Eclipse says jre does not support the current compiler level of 1.8 but it is set at 1.7
body: <p>I installed Eclipse mars with java JDK8 but was was having lots of problems with it so I uninstalled it changed back to JDK7 and now I'm getting a strange compiler error in a few of my projects. I noticed that when I went into, Windows->Preferences-> Java->Installed JREs, there is an error message at the top saying that "The selected JRE does not support the ...rent compiler compliance level of 1.8" but when I check the compiler compliance level its set to 1.7</p>
  
  <p>Ok so I decided to try starting a new project and  when trying to build it a warning came up that my workspace compliance level was at level 1.8...changing the workspace fixed the problem. So new is it possible to change the workspace compliance level or should I just import my projects into a new workspace?</p>
  
  <p>I tried importing into a new workspace,same problem. So I started new project in a new workspace, copyed and pasted the code in a voila it works! Very annoying if I have to do that for every class in every project I want.</p>