I'm trying to make a basic cache of a boolean value, and I did it like such:private Boolean _valueCache = null;private boolean getValue() {    try {        if (_valueCache == null) { // if cache was never filled            return _valueCache = getReader().getMyBooleanProperty(); // fill it and return the new value        }        return _valueCache; // else, return the cache    } catch (NullPointerException ex) { // getReader() returned null        return false; // that return may not be null in the future, so set nothing    }}Does this go against best practices? (letting a Boolean have 3 values: true, false, and null) I only want to cache this value, so I don't want to make an entire custom HashMap that mimics this behavior with a get-or-default method. That said, I've never done a cache this small so I don't know the downsides to it.To clarify, I meant ternary as in 3-state, as opposed to binary as in 2-state. Sorry for any confusion.
Can a Java Boolean be used for ternary (3-state) logic?
java;programming practices;boolean
You're not doing ternary logic, you're just using null as a placeholder for a missing value that happens to be of type Boolean. (Not having true nor false isn't quite the same as having one of the two but not knowing which.) Using null this way is a fairly common practice, but I wouldn't call it a good one.It's unlikely to cause you problems in this particular case because it's only used internally within a very small scope, but in general you would want to use Optional instead. Since any non-primitive variable could have null, it's very difficult to keep track of it in a large code base. The easiest way to avoid the issue is to not use null in the first place.