Ah. My apologies. The .bash_profile file should be located in your home directory. To get there, open up a console/terminal (command line) and do a "cd $HOME". This will move you to your home directory, which is at /home/<username>. From there, you can do a: user@localhost~$echo "export PATH=$PATH:/path/to/java" >> .bash_profile, which should append the line to the .bash_profile file. If neither of them are there, you can create them with "touch <filename>". Be sure to do a "ls -a" before though to view all of the files in the directory and make sure you are not overwriting anything.
you can also just execute the command ~$export PATH=$PATH:/path/to/java from the command line to have the settings apply right away. Do a ~$echo $PATH to see what is currently in your path and to verify.
you also might want to read up a little on the linux filesystem hierarchy and common bash commands to make your life a little bit easier.
http://tldp.org/ is a good place to start.