#502 Replaced usages of System.out with logger.

double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/App.java

@@ -22,6 +22,9 @@
  */
 package com.iluwatar.doublechecked.locking;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
@@ -40,6 +43,8 @@ import java.util.concurrent.TimeUnit;
  */
 public class App {
 
+  private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
+
   /**
    * Program entry point
    * 
@@ -58,7 +63,7 @@ public class App {
     try {
       executorService.awaitTermination(5, TimeUnit.SECONDS);
     } catch (InterruptedException e) {
-      System.out.println("Error waiting for ExecutorService shutdown");
+      LOGGER.error("Error waiting for ExecutorService shutdown");
     }
   }
 }

double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Inventory.java

@@ -22,6 +22,9 @@
  */
 package com.iluwatar.doublechecked.locking;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -35,6 +38,8 @@ import java.util.concurrent.locks.ReentrantLock;
  */
 public class Inventory {
 
+  private static final Logger LOGGER = LoggerFactory.getLogger(Inventory.class);
+
   private final int inventorySize;
   private final List<Item> items;
   private final Lock lock;
@@ -57,8 +62,7 @@ public class Inventory {
       try {
         if (items.size() < inventorySize) {
           items.add(item);
-          System.out.println(Thread.currentThread() + ": items.size()=" + items.size()
-              + ", inventorySize=" + inventorySize);
+          LOGGER.info("{}: items.size()={}, inventorySize={}", Thread.currentThread(), items.size(), inventorySize);
           return true;
         }
       } finally {