Chapter 8.3.2.2. paragraph 2:
Initialization expressions for instance variables are permitted to refer to the current object this (§15.8.3) and to use the keyword super (§15.11.2, §15.12).
Although the next paragraph adds:
Use of instance variables whose declarations appear textually after the use is sometimes restricted, even though these instance variables are in scope. See §8.3.2.3 for the precise rules governing forward reference to instance variables.