What is the BooleanUtils.isFalse method in Java?

The isFalse static method of the BooleanUtils class can be used to check if the Boolean value passed is equal to false.

Syntax

public static boolean isFalse(Boolean bool);

Argument

The isFalse method takes the Boolean object as an argument.

Return value

This method returns true if the passed argument is equal to false. Otherwise, false is returned. If we pass null then false is returned.

Import BooleanUtils

BooleanUtils is defined in the Apache Commons Lang package. Apache Commons Lang can be added to the Maven project by adding the following dependency to the pom.xml file.

<dependency>
   <groupId>org.apache.commons</groupId>
   <artifactId>commons-lang3</artifactId>
   <version>3.12.0</version>
</dependency>

For other versions of the commons-lang package, refer to the Maven Repository.

Possible case

BooleanUtils.isFalse

Case

Result

BooleanUtils.isFalse(Boolean.TRUE)

false

BooleanUtils.isFalse(Boolean.FALSE)

true

BooleanUtils.isFalse(null)

false

Code

In the code below, we have used the isFalse method as follows.

import org.apache.commons.lang3.BooleanUtils;
class ISFalseExample {
    public static void main( String args[] ) {
        System.out.println("BooleanUtils.isFalse(Boolean.TRUE) => " + BooleanUtils.isFalse(Boolean.TRUE)); // false
        System.out.println("BooleanUtils.isFalse(Boolean.FALSE) => " + BooleanUtils.isFalse(Boolean.FALSE)); // true
        System.out.println("BooleanUtils.isFalse(null) => " + BooleanUtils.isFalse(null)); // false
    }
}

Explanation

In the code above:

  • On line, 1 we imported the BooleanUtils class.
import org.apache.commons.lang3.BooleanUtils;
  • From lines 5 to 8, we used the isFalse method to check if the passed argument is false.
  • Below is the output.
BooleanUtils.isFalse(Boolean.TRUE); // false

BooleanUtils.isFalse(Boolean.FALSE); // true

BooleanUtils.isFalse(null); // false
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