[JAVA-9019] Move sysout lines to info logging

core-java-modules/core-java-collections-3/src/main/java/com/baeldung/collections/iterators/Iterators.java

@@ -1,17 +1,16 @@
 package com.baeldung.collections.iterators;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.concurrent.ConcurrentHashMap;
 
-/**
- * Source code https://github.com/eugenp/tutorials
- *
- * @author Santosh Thakur
- */
-
 public class Iterators {
 
+    private static final Logger LOG = LoggerFactory.getLogger(Iterators.class);
+
     public static int failFast1() {
         ArrayList<Integer> numbers = new ArrayList<>();
 
@@ -44,7 +43,7 @@ public class Iterators {
             }
         }
 
-        System.out.println("using iterator's remove method = " + numbers);
+        LOG.debug("using iterator's remove method = {}", numbers);
 
         iterator = numbers.iterator();
         while (iterator.hasNext()) {

core-java-modules/core-java-collections-3/src/test/java/com/baeldung/collections/bitset/BitSetUnitTest.java

@@ -3,6 +3,8 @@ package com.baeldung.collections.bitset;
 import org.junit.Test;
 import org.openjdk.jol.info.ClassLayout;
 import org.openjdk.jol.info.GraphLayout;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.BitSet;
 
@@ -10,18 +12,20 @@ import static org.assertj.core.api.Assertions.assertThat;
 
 public class BitSetUnitTest {
 
+    private static final Logger LOG = LoggerFactory.getLogger(BitSetUnitTest.class);
+
     @Test
     public void givenBoolArray_whenMemoryLayout_thenConsumeMoreThanOneBit() {
         boolean[] bits = new boolean[1024 * 1024];
 
-        System.out.println(ClassLayout.parseInstance(bits).toPrintable());
+        LOG.debug(ClassLayout.parseInstance(bits).toPrintable());
     }
 
     @Test
     public void givenBitSet_whenMemoryLayout_thenConsumeOneBitPerFlag() {
         BitSet bitSet = new BitSet(1024 * 1024);
 
-        System.out.println(GraphLayout.parseInstance(bitSet).toPrintable());
+        LOG.debug(GraphLayout.parseInstance(bitSet).toPrintable());
     }
 
     @Test
@@ -157,7 +161,7 @@ public class BitSetUnitTest {
         BitSet bitSet = new BitSet();
         bitSet.set(15, 25);
 
-        bitSet.stream().forEach(System.out::println);
+        bitSet.stream().forEach(bit -> LOG.debug(String.valueOf(bit)));
         assertThat(bitSet.stream().count()).isEqualTo(10);
     }
 

core-java-modules/core-java-collections-3/src/test/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>