apt-get upgrade: packages have been kept back

[ML mail <mlnospam@yahoo.com>]

Hi,

I was wondering why an "apt-get upgrade"on my Debian wheezy box does not want to update the OpenJDK packages as you can see below:


shell$ apt-get upgrade


Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages have been kept back:
icedtea-6-jre-cacao icedtea-6-jre-jamvm openjdk-6-jre openjdk-6-jre-headless openjdk-6-jre-lib
0 upgraded, 0 newly installed, 0 to remove and 5 not upgraded.

Anyone has an idea why they are all kept back? Is something broken on my side maybe?

Regards
ML