Commons Lang、BooleanUtils.toBooleanObject()

import org.apache.commons.lang.BooleanUtils;

public class C2009032500 {
    public static void main(String[] args) {
        System.out.println(BooleanUtils.toBooleanObject(true));
        System.out.println(BooleanUtils.toBooleanObject(false));
        System.out.println("***");
        System.out.println(BooleanUtils.toBooleanObject(new Integer(2)));
        System.out.println(BooleanUtils.toBooleanObject(new Integer(1)));
        System.out.println(BooleanUtils.toBooleanObject(new Integer(0)));
        System.out.println(BooleanUtils.toBooleanObject(new Integer(10), new Integer(10), new Integer(20), new Integer(30)));
        System.out.println(BooleanUtils.toBooleanObject(new Integer(20), new Integer(10), new Integer(20), new Integer(30)));
        System.out.println(BooleanUtils.toBooleanObject(new Integer(30), new Integer(10), new Integer(20), new Integer(30)));
        System.out.println("***");
        System.out.println(BooleanUtils.toBooleanObject(2));
        System.out.println(BooleanUtils.toBooleanObject(1));
        System.out.println(BooleanUtils.toBooleanObject(0));
        System.out.println(BooleanUtils.toBooleanObject(10, 10, 20, 30));
        System.out.println(BooleanUtils.toBooleanObject(20, 10, 20, 30));
        System.out.println(BooleanUtils.toBooleanObject(30, 10, 20, 30));
        System.out.println("***");
        System.out.println(BooleanUtils.toBooleanObject("true"));
        System.out.println(BooleanUtils.toBooleanObject("on"));
        System.out.println(BooleanUtils.toBooleanObject("yes"));
        System.out.println(BooleanUtils.toBooleanObject("false"));
        System.out.println(BooleanUtils.toBooleanObject("off"));
        System.out.println(BooleanUtils.toBooleanObject("no"));
        System.out.println(BooleanUtils.toBooleanObject("TRUE"));
        System.out.println(BooleanUtils.toBooleanObject("foo"));
        System.out.println(BooleanUtils.toBooleanObject("10", "10", "20", "30"));
        System.out.println(BooleanUtils.toBooleanObject("20", "10", "20", "30"));
        System.out.println(BooleanUtils.toBooleanObject("30", "10", "20", "30"));
    }
}

で、

true
false
***
true
true
false
true
false
null
***
true
true
false
true
false
null
***
true
true
true
false
false
false
true
null
true
false
null