java Parse Boolean that may be null to Boolean

Question

I noticed an issue with java.lang.Boolean class that it can not parse nulls. I know it has the parseBoolean static method but as it's signature states it only accepts String and not an Object.

In other words, it has the following signature:

public static boolean parseBoolean(String s)

but not:

Boolean.parseBoolean(Object)

What is the best way to check a Boolean value without falling on NullPointerException?

What are you trying to do? Convert a Boolean (that is either true, false, or null) into a boolean? If so, you'll have to decide whether you want nulls to be true or false. — Stack Exchange Broke The Law
– Stack Exchange Broke The Law, Commented Jan 20, 2016 at 9:05
Do you think, parseBoolean(null) is only applicable for parseBoolean(Object)? If not, how do you want your Objects to be parsed to Boolean? — steffen
– steffen, Commented Jan 20, 2016 at 9:11
I receive from an object entity a field that mus be Boolean (because it is entity) and null is of course false. So i think the best answer is just to compare it to Boolean.TRUE — Yuval Zilberstein
– Yuval Zilberstein, Commented Jan 21, 2016 at 10:18

Radoslav Ivanov · Accepted Answer · 2018-05-22 04:59:50Z

13

Try that approach:

Boolean.TRUE.equals(yourObj);

edited May 22, 2018 at 4:59

answered Jun 28, 2017 at 5:02

Radoslav Ivanov

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1 Comment

StevenWernerCS Over a year ago

OP might want the null. The question says into Boolean not boolean, still useful for others that just need the primitive

Chet · Accepted Answer · 2019-02-15 17:36:16Z

9

If you want your parse to return true, false or null as a Boolean object, take a look at Apache Commons Lang. BooleanUtils has a one liner that does exactly this.

https://commons.apache.org/proper/commons-lang/javadocs/api-2.4/org/apache/commons/lang/BooleanUtils.html#toBooleanObject(java.lang.String)

BooleanUtils.toBooleanObject(null) == null
BooleanUtils.toBooleanObject("true") == true
BooleanUtils.toBooleanObject("false") == false
BooleanUtils.toBooleanObject("YES") == true
BooleanUtils.toBooleanObject("nO") == false

answered Feb 15, 2019 at 17:36

Chet

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Comments

Yuval Zilberstein · Accepted Answer · 2016-01-20 09:04:35Z

-1

You can compare it to Boolean.TRUE or Boolean.FALSE. Example:

if (Boolean.TRUE == Box.modeled()) { //do somthing }

answered Jan 20, 2016 at 9:04

Yuval Zilberstein

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3 Comments

AdamSkywalker Over a year ago

this is actually bad because technically you can create new Boolean objects : Boolean b = new Boolean(true); b != Boolean.TRUE

Stultuske Over a year ago

so ... you answer your own question the very same moment you ask it?

AdamSkywalker Over a year ago

also this does not answer your question

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