Installing Java Development Tools in Flex Builder

Here are the simple steps to follow to install java development tools in FB3

1. go to Help->software update -> find and install.... which will open install/update dialog box.
2. select search for new features to install and click Next.
3. you will see install dialog box, select Europa Discovery Site and click finish.
4. then updates dialog box pops up, select java development packagae to install and click next (if you get any error click on the select required which solves your error)
5. accept the license and click finish.

That's it you are done, now you can write java code inside your flex builder IDE.