[~] # emerge -uvaND world                      

These are the packages that would be merged, in order:

Calculating world dependencies... done!
[blocks B     ] dev-java/java-config-wrapper (is blocking dev-java/java-config-1.2.11-r1)
(...)

Total size of downloads: 212,423 kB
Portage overlays:
 [1] /usr/local/portage

!!! Error: The above package list contains packages which cannot be installed
!!!        at the same time on the same system.

[~] # emerge -C java-config-wrapper 

--- Couldn't find 'java-config-wrapper' to unmerge.

>>> No packages selected for removal by unmerge.

[~] #