I have an Eclipse "sandbox" project that I use to test little SWT snippets. While trying to run one such snippet after upgrading to Eclipse Juno (4.2.0), I got the following exception:
The snippet worked prior to the upgrade. I checked my classpath and the org.eclipse.core.runtime JAR was in the list. It turns out that many of the classes in the package org.eclipse.core.runtime are now in the org.eclipse.equinox.common JAR.