Re: Why the Java Runaround?
The "Alternatives" system is something Debian first introduced to deal with several packages providing the same command. The default command is simply a link to the alternatives directory, which then redirects it to the appropriate binary. It's used by several 'generic' commands as well, like 'x-www-browser', 'editor' and so on.
Originally Posted by Andavane
In Java's case, this allows you to have multiple versions of the JVM installed, and use alternatives to set the default. You can use 'update-alternatives' to set the defaults for all commands registered with alternatives. See man update-alternatives.
As an aside, the command output you've indicated above seems abnormal. I'd expect /etc/alternatives/java to redirect to the java binary, not the man page for it.