Shortcut to Eclipse in /Applications
A symlink won't work as at the command line level an application is a directory.

Make an alias to the Eclipse application in the Finder and drop that into /Applications and it will work fine.

By the way, you will see in the eclipse folder a file eclipse which is a link to the actual Eclipse unix executable that lives in Eclipse.app/Contents/MacOS alongside the eclipse.ini file that defines all the startup options. You might want to replicate that link to somewhere in your PATH so that you can run Eclipse from the command line.