boolean rhs; rhs = value == null; Specifically, the part I don't understand is the = operator followed by value followed by ==. What does that mean?
4 Answers
Since comparing == has higher priority than = assigning, code
rhs = value == null; is the same as
rhs = (value == null); So it will check if value is null and store result of that test in rhs.
Comments
value == null is a boolean expression which evaluates to true if value == null, otherwise it is false. The value of this expression is assigned to rhs
The 2 statements are equivalent to
boolean rhs; if (value == null) rhs = true; else rhs false; 
Comments
It is assigning to the boolean variable rhs the result of evaluating: value == null
Comments
This is the simple way to check whether the the value is null or not. If null then is will assign true to rhs, else false. You can try it by your self using following code:
String value = null; String value2 = "Testing"; boolean rhs; System.out.println(rhs=value == null); //print true System.out.println(rhs); System.out.println(rhs=value2 == null);//print false System.out.println(rhs); 
if (value == null) rhs = true; else rhs = false, but just shorter...