unable to break blocks in adventure mode

In adventure mode, you can't break blocks.

only if i switch from creative to survival via /gamemode 1,/gamemode 2
then i cant break any blocks at all

and it is not resovled

survival is gamemode 0, not 2.

oohhhhh i get it now
thank u

I tried adventure mode in 1.7.10 update and I don't get this bug. Because it won't break.

It's intended. In 1.8, Adventure Mode has been changed to remove block breaking and placing without an item that explicitly allows it in its NBT.