The boolean keyword in Java is employed to declare a variable as a boolean type, representing either true or false. For instance:

boolean isLiving;

Additionally, the boolean keyword can be utilized to specify the return type of a method:

public boolean hasBundlesOfJoy() {
    return true;
}

In this example, the method hasBundlesOfJoy() returns a boolean value, indicating whether the entity in question has children (in this case, always returning true).