Add the blocks to a List, then it's just one single if statement in your event to check if whatever block is being broken is breakable. Much better than tons of chained else-ifs, though you still need to initialize the list by putting all the allowed blocks you want in there.

 

However, why do you need to make a list when there is already the 'isToolEffective' method? Surely that's enough for your needs, as you are only trying to restrict players from breaking blocks with fists, clumps of dirt, etc., right?

 

EDIT: I saw your code in another of your posts; you don't need to setCanceled(false), because the default behavior is to not be canceled. Besides, I'm pretty sure all of those blocks you checked for don't need a tool to break anyway, so isToolEffective will return true, and the event will not cancel, allowing the block to be broken by hand.

Yeah that makes more sense, I will most likely edit it today or tomorrow, just wanted to get it working.