Your *real* java executable isn't listed in that list (or have you actually broken the alternatives system and copied it into /usr/bin? ), so could you tell me which JRE distribution you are using, and where the actual java executable is located (readlink -f `which java`)? It probably isn't named anything remotely related to the word "java" as is common in some embedded JREs.
JamVM
david@beagleboard:~$ ls -l /usr/bin/jamvm
-rwxr-xr-x 1 root root 157924 Mar 15 2009 /usr/bin/jamvm
there's no jamvmws, either.
Don't look at me if directories are weird, I just installed the package!
If there was something like 'yum' for Debian-like packages, I'd tell you to use "yum provides */bin/javaws" but since there isn't anything like that...