Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
openjdk-7-jdk : Depends: openjdk-7-jre (>= 7~u3-2.1.1~pre1-1ubuntu2) but it is not going to be installed
Recommends: libxt-dev but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
fontes
deb link universo principal preciso deb-src link universo principal preciso
Finalmente descobri a solução por hit e julgamento. Em /etc/apt/sources.list substituído precise com trusty e tudo funciona. Agora posso instalar o pacote openjdk-7-jdk .
Depois de alterá-lo, /etc/apt/sources.list se parece com isso.
deb http://ports.ubuntu.com/ubuntu-ports/ trusty main universe
deb-src http://ports.ubuntu.com/ubuntu-ports/ trusty main universe