I wanted to add that you can check the bitness of your java version using the following commands as well:

1. java -d32  -version (returns an error if the java version is 64 bit)

2. java -d64 -version (returns an error if the java version is 32 bit)

Here is a screen shot running the above commands against my 64-bit java on windows.

Also contrary to one of the earlier posts, I believe that a full jdk is not required to run Atelier or eclipse. A jre is sufficient.