hamiljf,
Our current releases do not support Java 8 by default.The MyEclipse 2015 GA will have support for Java 8. The release is due towards the end of May 2014.
To add Java 8 support to MyEclipse 2014, install the Kepler Java 8 patch to a standard Kepler SR2 install and then install MyEclipse from the update site. It is then possible to install the Java 8 facet patch for WTP.
For the MyEclipse update site, please check this link : http://www.myeclipseide.com/index.php?name=Recommend_Us&req=Download&version=ME
Let us know how it works for you.