In older version NetBeans default uninstall location was /usr/local/netbeansxxxx

but in new versions they have changed installation locations actually, you can decide to which location to install

in new versions you can easily find the installed location just right click and checking properties of NetBeans Desktop icon

In my case i have installed it in my Home folder, i opened terminal,moved to installation location using cd /installation path
*change installation path to yours

In your terminal it will looks like this

type

./uninstall.sh

press enter

uninstall

Enjoy.