Commons Lang、Validate.isTrue()

everyday Java 
import org.apache.commons.lang.Validate;

public class C2009051000 {
    public static void main(String[] args) {
        Validate.isTrue(true,  "foo", 100);

        Validate.isTrue(false, "foo", 100);
    }
}

で、

Exception in thread "main" java.lang.IllegalArgumentException: foo100
	at org.apache.commons.lang.Validate.isTrue(Validate.java:101)
	at C2009051000.main(C2009051000.java:8)