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Editorial Team
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Asked: 2026-06-06T15:07:08+00:00

Java boolean allows values of true and false while Boolean allows true , false

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Java boolean allows values of true and false while Boolean allows true, false, and null. I have started to convert my booleans to Booleans. This can cause crashes in tests such as

Boolean set = null;
...
if (set) ...

while the test

if (set != null && set) ...

seems contrived and error-prone.

When, if ever, is it useful to use Booleans with null values? If never, then what are the main advantages of the wrapped object?

UPDATE:
There has been such a lot of valuable answers that I have summarised some of it in my own answer. I am at best an intermediate in Java so I have tried to show the things that I find useful. Note that the question is “incorrectly phrased” (Boolean cannot “have a null value”) but I have left it in case others have the same misconception

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1 Answer

  1. Editorial Team

    Use boolean rather than Boolean every time you can. This will avoid many NullPointerExceptions and make your code more robust.

    Boolean is useful, for example

    • to store booleans in a collection (List, Map, etc.)
    • to represent a nullable boolean (coming from a nullable boolean column in a database, for example). The null value might mean “we don’t know if it’s true or false” in this context.
    • each time a method needs an Object as argument, and you need to pass a boolean value. For example, when using reflection or methods like MessageFormat.format().
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