package com.conveyal.gtfs.model;

import java.util.ArrayList;
import java.util.List;


public class ValidationResult {
	
	public List<InvalidValue> invalidValues = new ArrayList<InvalidValue>();
	
	public void add(InvalidValue iv) {
		System.out.println(iv);
		invalidValues.add(iv);
	}
	
	public void add(ValidationResult vr) {
		invalidValues.addAll(vr.invalidValues);
	}
}

@@ -78,16 +78,49 @@
 l.List;%0A
+import java.util.logging.Logger;%0A
 %0A%0Apublic
@@ -146,17 +146,101 @@
 sult %7B%0A%09
+private static Logger _log = Logger.getLogger(ValidationResult.class.getName());%0A%09%09%09
 %0A
-
 %09public 
@@ -349,29 +349,31 @@
 %7B%0A%09%09
-System.out.println(iv
+_log.info(iv.toString()
 );%0A%09

Use java.util.logging in the library. Fix #3.