Eclipse 4.2 , android developers tools

Just loaded one latest eclipse Classic IDE.

Try to install the developers tools, get an error,

cannot complete the install because one or more required items could not be found.   Software being installed: Android Development Tools 20.0.0.v201206242043-391819 (com.android.ide.eclipse.adt.feature.group 20.0.0.v201206242043-391819)   Missing requirement: Android Development Tools 20.0.0.v201206242043-391819(com.android.ide.eclipse.adt.feature.group 20.0.0.v201206242043-391819) requires 'org.eclipse.wst.sse.core 0.0.0' but it could not be found

basically, the error means it need the wst feature, just insall the web feature, then the installation will go through,