john@ubuntu:~$ sudo update-alternatives --config java
[sudo] password for john:
There is only one alternative in link group java (providing /usr/bin/java): /usr/lib/jvm/java-7-openjdk-amd64/bin/java
Nothing to configure.
john@ubuntu:~$ sudo dpkg --configure icedtea-netx
Setting up icedtea-netx:amd64 (1.5.1-1ubuntu1) ...
update-alternatives: warning: forcing reinstallation of alternative /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/itweb-settings because link group itweb-settings is broken
update-alternatives: warning: not replacing /usr/share/man/man1/itweb-settings.1.gz with a link
update-alternatives: warning: forcing reinstallation of alternative /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/itweb-settings because link group itweb-settings is broken
update-alternatives: warning: not replacing /usr/share/man/man1/itweb-settings.1.gz with a link
update-alternatives: error: alternative path /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/javaws doesn't exist
dpkg: error processing package icedtea-netx:amd64 (--configure):
 subprocess installed post-installation script returned error exit status 2
Errors were encountered while processing:
 icedtea-netx:amd64
john@ubuntu:~$