Dynamically set JAVA_HOME based on OS

Set JAVA_HOME correctly on OS X Lion and Ubuntu 11.04.

Ubuntu 11.04 is currently my Linux of choice. If this logic proves to
not be portable to other Linuxes that I use in the future, then I'll
update the logic at that time.

bash/paths

@@ -1,4 +1,9 @@
-export JAVA_HOME=$(/usr/libexec/java_home)
+if [[ "$PLATFORM" == 'osx' ]]; then
+  export JAVA_HOME=$(/usr/libexec/java_home)
+elif [[ "$PLATFORM" == 'linux' ]]; then
+  # Credit: http://serverfault.com/a/143838
+  export JAVA_HOME=$(readlink -f /usr/bin/java | sed "s:bin/java::")
+fi
 
 export PATH="~/bin:~/src/etc/scripts:/usr/local/bin:/usr/local/sbin:$PATH"
 export MANPATH="/usr/local/man:/usr/local/mysql/man:/usr/local/git/man:$MANPATH"

bashrc

@@ -2,6 +2,8 @@ PLATFORM='unknown'
 unamestr=`uname`
 if [[ "$unamestr" == 'Darwin' ]]; then
   PLATFORM='osx'
+elif [[ "$unamestr" == 'Linux' ]]; then
+  PLATFORM='linux'
 fi
 
 source ~/.bash/aliases