sure, i guess this could work around space constraints for you...
here's what's going on:
you moved the top directory -- that moves all the files and subdirectories under it, so
wherever the top directory is, the subdirectories and files are.
you symbolically linked at the top-directory level. now if you cd to /usr/java, you are not
working from /usr/java, because that directory does not exist, but you followed the link
to /home/Program_Files/java, and that is actually your working directory, though because
you followed the symbolic link to get there, it might look like it's /usr/java
linux symbolic links do not work like windows shortcuts. the symbolic links are all
but seamless in the file structure -- it only looks like there are two copies.