Is it possible to change the grid size of the home page using Jelly Bean 4.2.2 without rooting phone ?
There are two ways known to me how this could be achieved:
Using a launcher which supports this
There are several launchers available on Google Play which let you configure the grid size of your homescreen as well as of your app drawer. One of those is Apex Launcher, which I use myself. Another example is GO Launcher EX, which I run on another device. I'm pretty sure a load of other launchers does this as well.
EDIT: Holy whatever. If that's not enough, take a look at Lighning Launcher. Grid size? What grid? Who needs a grid? Icon size, font size, orientation -- feel free to design your own homescreen! And now, for the size of the package. Sitting? 200 kB (still looking for the hook), working with Android 1.6 and up. Truly AMAZING!
Ah, and what comes below: Multi-whatever is already included. Widgets in folders? No problem, either... Well, that bunch of features must need permis... what? Only USB-Storage? Can't believe... I just sent it to one of my devices to take a closer look :)
There are some sort of "widget expanders" out there, which pick 4 (or more) widgets and combine them into one "compressed widget". One example for this group is Multicon Widget.