title: Java version, Tomcat, Unsupported major.minor version 52.0
body: <p>I am working on an app and I built the back end part with Java and Jersey which is hosted on my server. I use Tomcat7 on the server to be able to call the web services.</p>
  
  <p>I had a previous computer with Ubuntu, I used to export my project to a war file, put it in the Tomcat folder and it worked. I now changed my computer to a Mac, I have the exact same Java project, which works when I run it locally on my computer. But when I upload it to the server the same way as before, I have this error : <code>Unsupported major.minor version 52.0</code>.</p>
  
  <p>I checked many websites and understood it was a Java Version problem. So I tried many changes but it didn't work.</p>
  
  <ul>
  <li><p>On my server I have : Ubuntu, tomcat7 and java-7-openjdk-amd64. In /etc/default/tomcat7, there's a line : <code>JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64.</code></p></li>
  <li><p>On my previous computer (Ubuntu), I used Eclipse and Java 8. And the generated war worked with the server.</p></li>
  <li><p>On my new computer (Mac), I also use Eclipse and Java 8 but the war files won't work on the server.</p></li>
  </ul>
  
  <p>I tried to change the version of the compiler in Eclipse to Java 1.7 but I still have the same error.</p>
  
  <p>Does anybody have any idea to fix this problem ? Thanks in advance for help </p>
  
  <p>All the best.</p>