When writing an expression in math to say something along the lines of "x is greater than zero and less than 5," it is natural to put that x in the middle of both operators like so.

0 < x < 5

This does not work in Java. In order to "chain" comparisons like this, you have to combine the results of comparisons using the && operator.

boolean xInRange = 0 < x && x < 5;