I'm mostly a C# developer, although I have a little Java background. But I think my answer applies to both. I suspect it's not an intentional feature, but more of an emergent feature. The grammar of the language goes (roughly)
if (*condition*)
*statement*
Unfortunately the below are both valid statements (I checked, you can drop as many into C# as you like and the compiler doesn't complain):
;
{
}
Therefore the construct that you highlighted is allowed.
