diff --git a/core-java-9/src/main/java/com/baeldung/multireleaseapp/App.java b/core-java-9/src/main/java/com/baeldung/multireleaseapp/App.java
index c2e738384a..21bbcc01d4 100644
--- a/core-java-9/src/main/java/com/baeldung/multireleaseapp/App.java
+++ b/core-java-9/src/main/java/com/baeldung/multireleaseapp/App.java
@@ -1,11 +1,16 @@
 package com.baeldung.multireleaseapp;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 public class App {
 
+    private static final Logger logger = LoggerFactory.getLogger(App.class);
+    
     public static void main(String[] args) throws Exception {
         String dateToCheck = args[0];
         boolean isLeapYear = DateHelper.checkIfLeapYear(dateToCheck);
-        System.out.println("Date given " + dateToCheck + " is leap year: " + isLeapYear);
+        logger.info("Date given " + dateToCheck + " is leap year: " + isLeapYear);
     }
 
 }
diff --git a/core-java-9/src/main/java/com/baeldung/multireleaseapp/DateHelper.java b/core-java-9/src/main/java/com/baeldung/multireleaseapp/DateHelper.java
index 842ac00350..4d943db30b 100644
--- a/core-java-9/src/main/java/com/baeldung/multireleaseapp/DateHelper.java
+++ b/core-java-9/src/main/java/com/baeldung/multireleaseapp/DateHelper.java
@@ -2,23 +2,21 @@ package com.baeldung.multireleaseapp;
 
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
+import java.util.GregorianCalendar;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class DateHelper {
 
+    private static final Logger logger = LoggerFactory.getLogger(DateHelper.class);
+
     public static boolean checkIfLeapYear(String dateStr) throws Exception {
-        System.out.println("Checking for leap year using Java 1 calendar API ");
-        boolean isLeapYear = false;
+        logger.info("Checking for leap year using Java 1 calendar API");
         Calendar cal = Calendar.getInstance();
         cal.setTime(new SimpleDateFormat("yyyy-MM-dd").parse(dateStr));
         int year = cal.get(Calendar.YEAR);
-        if (year % 4 == 0) {
-            if (year % 100 == 0) {
-                isLeapYear = (year % 400 == 0) ? true : false;
-            } else {
-                isLeapYear = true;
-            }
-        }
-        return isLeapYear;
+        return (new GregorianCalendar()).isLeapYear(year);
     }
 
 }
diff --git a/core-java-9/src/main/java9/com/baeldung/multireleaseapp/DateHelper.java b/core-java-9/src/main/java9/com/baeldung/multireleaseapp/DateHelper.java
index 1d8a10f145..35fb0ada1e 100644
--- a/core-java-9/src/main/java9/com/baeldung/multireleaseapp/DateHelper.java
+++ b/core-java-9/src/main/java9/com/baeldung/multireleaseapp/DateHelper.java
@@ -2,10 +2,15 @@ package com.baeldung.multireleaseapp;
 
 import java.time.LocalDate;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 public class DateHelper {
 
+    private static final Logger logger = LoggerFactory.getLogger(DateHelper.class);
+
     public static boolean checkIfLeapYear(String dateStr) throws Exception {
-        System.out.println("Checking for leap year using Java 9 Date Api");
+        logger.info("Checking for leap year using Java 9 Date Api");
         return LocalDate.parse(dateStr)
             .isLeapYear();
     }