diff --git a/core-java-modules/core-java-collections-3/src/main/java/com/baeldung/collections/mapfirstpair/MapFirstPairExample.java b/core-java-modules/core-java-collections-3/src/main/java/com/baeldung/collections/mapfirstpair/MapFirstPairExample.java
new file mode 100644
index 0000000000..8e5fc296d4
--- /dev/null
+++ b/core-java-modules/core-java-collections-3/src/main/java/com/baeldung/collections/mapfirstpair/MapFirstPairExample.java
@@ -0,0 +1,42 @@
+package com.baeldung.collections.mapfirstpair;
+
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+
+public class MapFirstPairExample {
+
+    public Map.Entry<Integer, String> getFirstPairUsingIterator(Map<Integer, String> map) {
+        if (map == null || map.size() == 0)
+            return null;
+
+        Iterator<Map.Entry<Integer, String>> iterator = map.entrySet()
+            .iterator();
+
+        if (iterator.hasNext())
+            return iterator.next();
+
+        return null;
+    }
+
+    public Map.Entry<Integer, String> getFirstPairUsingStream(Map<Integer, String> map) {
+        if (map == null || map.size() == 0)
+            return null;
+
+        Set<Map.Entry<Integer, String>> entrySet = map.entrySet();
+
+        return entrySet.stream()
+            .findFirst()
+            .get();
+    }
+
+    public Map<Integer, String> populateMapValues(Map<Integer, String> map) {
+        if (map != null) {
+            map.put(5, "A");
+            map.put(1, "B");
+            map.put(2, "C");
+        }
+        return map;
+    }
+
+}
\ No newline at end of file
diff --git a/core-java-modules/core-java-collections-3/src/main/java/com/baeldung/collections/mapfirstpair/MapFirstPairService.java b/core-java-modules/core-java-collections-3/src/main/java/com/baeldung/collections/mapfirstpair/MapFirstPairService.java
deleted file mode 100644
index 5d3c4fac32..0000000000
--- a/core-java-modules/core-java-collections-3/src/main/java/com/baeldung/collections/mapfirstpair/MapFirstPairService.java
+++ /dev/null
@@ -1,17 +0,0 @@
-/**
- * 
- */
-package com.baeldung.collections.mapfirstpair;
-
-import java.util.Map;
-
-/**
- * @author ASHWINI
- *
- */
-public interface MapFirstPairService {
-
-    <K, V> Map.Entry<K, V> getFirstPairUsingIterator(Map<K, V> map);
-
-    <K, V> Map.Entry<K, V> getFirstPairUsingStream(Map<K, V> map);
-}
diff --git a/core-java-modules/core-java-collections-3/src/main/java/com/baeldung/collections/mapfirstpair/MapFirstPairServiceImpl.java b/core-java-modules/core-java-collections-3/src/main/java/com/baeldung/collections/mapfirstpair/MapFirstPairServiceImpl.java
deleted file mode 100644
index aff6430216..0000000000
--- a/core-java-modules/core-java-collections-3/src/main/java/com/baeldung/collections/mapfirstpair/MapFirstPairServiceImpl.java
+++ /dev/null
@@ -1,40 +0,0 @@
-/**
- * 
- */
-package com.baeldung.collections.mapfirstpair;
-
-import java.util.Iterator;
-import java.util.Map;
-import java.util.Set;
-
-/**
- * @author ASHWINI
- *
- */
-public class MapFirstPairServiceImpl implements MapFirstPairService {
-
-    public <K, V> Map.Entry<K, V> getFirstPairUsingIterator(Map<K, V> map) {
-        if (map == null || map.size() == 0)
-            return null;
-
-        Iterator<Map.Entry<K, V>> iterator = map.entrySet()
-            .iterator();
-
-        if (iterator.hasNext())
-            return iterator.next();
-
-        return null;
-    }
-
-    public <K, V> Map.Entry<K, V> getFirstPairUsingStream(Map<K, V> map) {
-        if (map == null || map.size() == 0)
-            return null;
-
-        Set<Map.Entry<K, V>> entrySet = map.entrySet();
-
-        return entrySet.stream()
-            .findFirst()
-            .get();
-    }
-
-}
\ No newline at end of file
diff --git a/core-java-modules/core-java-collections-3/src/test/java/com/baeldung/collections/mapfirstpair/MapFirstPairServiceUnitTest.java b/core-java-modules/core-java-collections-3/src/test/java/com/baeldung/collections/mapfirstpair/MapFirstPairUnitTest.java
similarity index 61%
rename from core-java-modules/core-java-collections-3/src/test/java/com/baeldung/collections/mapfirstpair/MapFirstPairServiceUnitTest.java
rename to core-java-modules/core-java-collections-3/src/test/java/com/baeldung/collections/mapfirstpair/MapFirstPairUnitTest.java
index 56e293ffc5..c8198bcc02 100644
--- a/core-java-modules/core-java-collections-3/src/test/java/com/baeldung/collections/mapfirstpair/MapFirstPairServiceUnitTest.java
+++ b/core-java-modules/core-java-collections-3/src/test/java/com/baeldung/collections/mapfirstpair/MapFirstPairUnitTest.java
@@ -11,30 +11,22 @@ import java.util.Map;
 import org.junit.Before;
 import org.junit.Test;
 
-public class MapFirstPairServiceUnitTest {
+public class MapFirstPairUnitTest {
 
-    private MapFirstPairService mapFirstPairService;
+    private MapFirstPairExample mapFirstPairExample;
 
     @Before
     public void Setup() {
 
-        mapFirstPairService = new MapFirstPairServiceImpl();
-    }
-
-    private void populateMapValues(Map<Integer, String> map) {
-        if (map != null) {
-            map.put(5, "A");
-            map.put(1, "B");
-            map.put(2, "C");
-        }
+        mapFirstPairExample = new MapFirstPairExample();
     }
 
     @Test
-    public void whenUsingIteratorForHashMap() {
+    public void whenUsingIteratorForHashMap_thenFirstPairWhichWasNotInsertedFirst() {
         Map<Integer, String> hashMap = new HashMap<>();
-        populateMapValues(hashMap);
+        hashMap = mapFirstPairExample.populateMapValues(hashMap);
 
-        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingIterator(hashMap);
+        Map.Entry<Integer, String> actualValue = mapFirstPairExample.getFirstPairUsingIterator(hashMap);
         Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(1, "B");
         Map.Entry<Integer, String> pairInsertedFirst = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
 
@@ -43,10 +35,10 @@ public class MapFirstPairServiceUnitTest {
     }
 
     @Test
-    public void whenUsingStreamForHashMap() {
+    public void whenUsingStreamForHashMap_thenFirstPairWhichWasNotInsertedFirst() {
         Map<Integer, String> hashMap = new HashMap<>();
-        populateMapValues(hashMap);
-        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingStream(hashMap);
+        hashMap = mapFirstPairExample.populateMapValues(hashMap);
+        Map.Entry<Integer, String> actualValue = mapFirstPairExample.getFirstPairUsingStream(hashMap);
         Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(1, "B");
         Map.Entry<Integer, String> pairInsertedFirst = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
 
@@ -55,21 +47,21 @@ public class MapFirstPairServiceUnitTest {
     }
 
     @Test
-    public void whenUsingIteratorForLinkedHashMap() {
+    public void whenUsingIteratorForLinkedHashMap_thenFirstPairWhichWasInsertedFirst() {
         Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
-        populateMapValues(linkedHashMap);
-        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingIterator(linkedHashMap);
+        linkedHashMap = mapFirstPairExample.populateMapValues(linkedHashMap);
+        Map.Entry<Integer, String> actualValue = mapFirstPairExample.getFirstPairUsingIterator(linkedHashMap);
         Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
 
         assertEquals(expectedValue, actualValue);
     }
 
     @Test
-    public void whenUsingStreamForLinkedHashMap() {
+    public void whenUsingStreamForLinkedHashMap_thenFirstPairWhichWasInsertedFirst() {
         Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
-        populateMapValues(linkedHashMap);
+        linkedHashMap = mapFirstPairExample.populateMapValues(linkedHashMap);
 
-        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingStream(linkedHashMap);
+        Map.Entry<Integer, String> actualValue = mapFirstPairExample.getFirstPairUsingStream(linkedHashMap);
         Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
 
         assertEquals(expectedValue, actualValue);
@@ -78,10 +70,10 @@ public class MapFirstPairServiceUnitTest {
     @Test
     public void whenAddedAnElementInHashMap_thenFirstPairChangedUsingIterator() {
         Map<Integer, String> hashMap = new HashMap<>();
-        populateMapValues(hashMap);
+        hashMap = mapFirstPairExample.populateMapValues(hashMap);
 
         hashMap.put(0, "D");
-        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingIterator(hashMap);
+        Map.Entry<Integer, String> actualValue = mapFirstPairExample.getFirstPairUsingIterator(hashMap);
         Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(0, "D");
 
         assertEquals(expectedValue, actualValue);
@@ -90,10 +82,10 @@ public class MapFirstPairServiceUnitTest {
     @Test
     public void whenAddedAnElementInHashMap_thenFirstPairChangedUsingStream() {
         Map<Integer, String> hashMap = new HashMap<>();
-        populateMapValues(hashMap);
+        hashMap = mapFirstPairExample.populateMapValues(hashMap);
 
         hashMap.put(0, "D");
-        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingStream(hashMap);
+        Map.Entry<Integer, String> actualValue = mapFirstPairExample.getFirstPairUsingStream(hashMap);
         Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(0, "D");
 
         assertEquals(expectedValue, actualValue);
@@ -102,10 +94,10 @@ public class MapFirstPairServiceUnitTest {
     @Test
     public void whenAddedAnElementInLinkedHashMap_thenFirstPairRemainUnchangedUsingIterator() {
         Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
-        populateMapValues(linkedHashMap);
+        linkedHashMap = mapFirstPairExample.populateMapValues(linkedHashMap);
 
         linkedHashMap.put(0, "D");
-        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingIterator(linkedHashMap);
+        Map.Entry<Integer, String> actualValue = mapFirstPairExample.getFirstPairUsingIterator(linkedHashMap);
         Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
 
         assertEquals(expectedValue, actualValue);
@@ -114,10 +106,10 @@ public class MapFirstPairServiceUnitTest {
     @Test
     public void whenAddedAnElementInLinkedHashMap_thenFirstPairRemainUnchangedUsingStream() {
         Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
-        populateMapValues(linkedHashMap);
+        linkedHashMap = mapFirstPairExample.populateMapValues(linkedHashMap);
 
         linkedHashMap.put(0, "D");
-        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingStream(linkedHashMap);
+        Map.Entry<Integer, String> actualValue = mapFirstPairExample.getFirstPairUsingStream(linkedHashMap);
         Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
 
         assertEquals(expectedValue, actualValue);