This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Because your reference only has two dimensions you can only use two dimensions in the shortcut syntax. The following will do exactly the same but will work:
I think the reason is that the actual type of the other arrays can no longer be determined. The first two dimension types can be read from the reference type, but after that it's not possible to see if it should be Object, String or anything else.