diff --git a/core-java-8/src/test/java/com/baeldung/counter/CounterStatistics.java b/core-java-8/src/test/java/com/baeldung/counter/CounterStatistics.java
index 2a42a166fa..015ca3f942 100644
--- a/core-java-8/src/test/java/com/baeldung/counter/CounterStatistics.java
+++ b/core-java-8/src/test/java/com/baeldung/counter/CounterStatistics.java
@@ -2,6 +2,7 @@ package com.baeldung.counter;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Random;
 
 import org.openjdk.jmh.annotations.Benchmark;
 import org.openjdk.jmh.annotations.BenchmarkMode;
@@ -18,8 +19,18 @@ public class CounterStatistics {
     private static final Map<String, MutableInteger> counterWithMutableIntMap = new HashMap<>();
     private static final Map<String, int[]> counterWithIntArrayMap = new HashMap<>();
     private static final Map<String, Long> counterWithLongWrapperMap = new HashMap<>();
+    private static final Map<String, Long> counterWithLongWrapperStreamMap = new HashMap<>();
+    
+    static {
+        CounterUtil.COUNTRY_NAMES = new String[10000];
+        final String prefix = "NewString"; 
+        Random random = new Random();
+        for (int i=0; i<10000; i++) {
+            CounterUtil.COUNTRY_NAMES[i] = new String(prefix + random.nextInt(1000));
+        }
+    }
 
-    @Benchmark
+  @Benchmark
     public void wrapperAsCounter() {
         CounterUtil.counterWithWrapperObject(counterMap);
     }
@@ -28,6 +39,11 @@ public class CounterStatistics {
     public void lambdaExpressionWithWrapper() {
         CounterUtil.counterWithLambdaAndWrapper(counterWithLongWrapperMap);
     }
+    
+    @Benchmark
+    public void parallelStreamWithWrapper() {
+        CounterUtil.counterWithParallelStreamAndWrapper(counterWithLongWrapperStreamMap);
+    }
 
     @Benchmark
     public void mutableIntegerAsCounter() {
diff --git a/core-java-8/src/test/java/com/baeldung/counter/CounterUtil.java b/core-java-8/src/test/java/com/baeldung/counter/CounterUtil.java
index afd7202892..c2bf47e213 100644
--- a/core-java-8/src/test/java/com/baeldung/counter/CounterUtil.java
+++ b/core-java-8/src/test/java/com/baeldung/counter/CounterUtil.java
@@ -6,7 +6,7 @@ import java.util.stream.Stream;
 
 public class CounterUtil {
 
-    private final static String[] COUNTRY_NAMES = { "China", "Australia", "India", "USA", "USSR", "UK", "China", "France", "Poland", "Austria", "India", "USA", "Egypt", "China" };
+    public static String[] COUNTRY_NAMES = { "China", "Australia", "India", "USA", "USSR", "UK", "China", "France", "Poland", "Austria", "India", "USA", "Egypt", "China" };
 
     public static void counterWithWrapperObject(Map<String, Integer> counterMap) {
         for (String country : COUNTRY_NAMES) {
@@ -15,9 +15,14 @@ public class CounterUtil {
     }
 
     public static void counterWithLambdaAndWrapper(Map<String, Long> counterMap) {
-        counterMap.putAll(Stream.of(COUNTRY_NAMES)
+        Stream.of(COUNTRY_NAMES)
+            .collect(Collectors.groupingBy(k -> k, () -> counterMap, Collectors.counting()));
+    }
+
+    public static void counterWithParallelStreamAndWrapper(Map<String, Long> counterMap) {
+        Stream.of(COUNTRY_NAMES)
             .parallel()
-            .collect(Collectors.groupingBy(k -> k, Collectors.counting())));
+            .collect(Collectors.groupingBy(k -> k, () -> counterMap, Collectors.counting()));
     }
 
     public static class MutableInteger {
@@ -49,4 +54,4 @@ public class CounterUtil {
         }
     }
 
-}
+}
\ No newline at end of file