title: Eclipse: export a Runnable JAR file to be executed on an older JRE
body: <p>Exporting a Runnable JAR file from Eclipse is by far the quickest way to launch an Eclipse project from command line on another machine. <a href="https://stackoverflow.com/a/5441852/2091700">See this answer</a>.</p>
  
  <p>A problem is that if the JRE installed on the machine you want to run from is older than the JDK used by Eclipse, you get this error:</p>
  
  <pre><code>java.lang.UnsupportedClassVersionError: test_hello_world : Unsupported major.minor version 51.0
  </code></pre>
  
  <p>I know that on Eclipse I can build the project with a lower compliance level (e.g., <code>1.6</code> instead of <code>1.7</code>), but this does not seem to affect an exported JAR file.</p>
  
  <p>Any idea on how to export a Runnable JAR file to be executed on an older JRE?</p>