Installation of cassandra fails of unmet dependencies
<p>I tried to install cassandra appache. I was following the steps in the <a href="https://wiki.apache.org/cassandra/DebianPackaging" rel="nofollow">debianpackaging wiki</a>. I've added the the two lines to my sources.list:</p>

<pre><code>ola@station:~$ cat /etc/apt/sources.list | grep "apache"
deb http://www.apache.org/dist/cassandra/debian 30x main
deb-src http://www.apache.org/dist/cassandra/debian 30x main
ola@station:~$ 
</code></pre>

<p>my java version looks fine as well:</p>

<pre><code>olas@station:~$ java -version
java version "1.8.0_60"
Java(TM) SE Runtime Environment (build 1.8.0_60-b27)
Java HotSpot(TM) 64-Bit Server VM (build 25.60-b23, mixed mode)
olas@station:~$ 
</code></pre>

<p>However, when I try to install it I get the following error message:</p>

<pre><code>olas@station:~$ sudo apt-get install cassandra
Reading package lists... Done
Building dependency tree       
Reading state information... Done
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:
 cassandra : Depends: openjdk-8-jre-headless but it is not installable or
                      java8-runtime but it is not installable
             Recommends: ntp but it is not going to be installed or
                         time-daemon
E: Unable to correct problems, you have held broken packages.
</code></pre>

<p>how can I resolve this?</p>