title: Eclipse: changing runtime Ant Home results in error popup regarding missing tools.jar library
body: <p>I was trying to change the runtime Ant version of my Eclipse IDE (Helios) from the outdated version built-in with Eclipse to the more robust and latest version saved elsewhere on my computer (Windows XP Professional). In order to do this change, I had to go to <strong>Window -> Preferences -> Ant -> Runtime -> Classpath</strong> and then change the <em>Ant Home</em> to the home directory of the newer Ant version. This results in the following yes-no popup message:  </p>
  
  <blockquote>The specified Ant runtime classpath does not include a tools.jar library. This may affect the ability to use various tasks. Ignore this possible problem?
  </blockquote>  
  
  <p>Even reverting back to the original built-in directory for <em>Ant Home</em> results in the same popup warning message. In addition, my Ant build.xml script runs just ok despite this warning.  </p>
  
  <p>I know there are some other SOF questions that state covers a similar problem: an error message during an Ant build script execution because tools.jar is missing. These questions seems to relate to a JAVA_HOME variable problem (<a href="https://stackoverflow.com/questions/2618281/ant-error-when-trying-to-build-file-cant-find-tools-jar">relevant question</a>). Is this what Eclipse was trying to warn me about? Or is this warning about something different? I believe I have ANT_HOME and JAVA_HOME variables set up properly on my computer.</p>