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How do you check if a boolean is null or not? So if I know "hideInNav" is null. How do I stop it from further executing? Something like the below doesn't seem to work but why?
boolean hideInNav = parent.getProperties().get("hideInNav", false); String hideNavigation = hideInNav != null ? hideInNav : ""; 
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Boolean testvar = null; if (testvar == null) { ...} Yes, because then hideInNav holds a reference to a Boolean object and can be null (no reference assigned). Therefor you can check if the reference is null .
Nullable boolean can be null, or having a value “true” or “false”. Before accessing the value, we should verify if the variable is null or not. This can be done with the classical check : if … else …
Java boolean operators are denoted by |, ||, &, &&, <, >, <=, >=, ^, != , ==. These logical boolean operators help in specifying the condition that will have the two return values – “true” or “false”.
You can't compare null to a boolean . They are different types one indicating a null reference pointer and the other a false/not true value. Thus the answer is: No this expression is not even valid (and if it was, it would be false).
boolean can only be true or false because it's a primitive datatype (+ a boolean variables default value is false). You can use the class Boolean instead if you want to use null values. Boolean is a reference type, that's the reason you can assign null to a Boolean "variable". Example:
Boolean testvar = null; if (testvar == null) { ...} A boolean cannot be null in java.
A Boolean, however, can be null.
If a boolean is not assigned a value (say a member of a class) then it will be false by default.
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