diff --git a/core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/SingleLock.java b/core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/SingleLock.java
index 84a82baff2..43c6c3e747 100644
--- a/core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/SingleLock.java
+++ b/core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/SingleLock.java
@@ -12,7 +12,7 @@ public class SingleLock extends ConcurrentAccessExperiment {
         lock = new ReentrantLock();
     }
 
-    protected synchronized Supplier<?> putSupplier(Map<String,String> map, int key) {
+    protected Supplier<?> putSupplier(Map<String,String> map, int key) {
         return (()-> {
             try {
                 lock.lock();
@@ -27,7 +27,7 @@ public class SingleLock extends ConcurrentAccessExperiment {
         });
     }
 
-    protected synchronized Supplier<?> getSupplier(Map<String,String> map, int key) {
+    protected Supplier<?> getSupplier(Map<String,String> map, int key) {
         return (()-> {
             try {
                 lock.lock();
diff --git a/core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/StripedLock.java b/core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/StripedLock.java
index ac94de6451..8b661ecedc 100644
--- a/core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/StripedLock.java
+++ b/core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/StripedLock.java
@@ -13,7 +13,7 @@ public class StripedLock extends ConcurrentAccessExperiment {
         stripedLock = Striped.lock(buckets);
     }
 
-    protected synchronized Supplier<?> putSupplier(Map<String,String> map, int key) {
+    protected Supplier<?> putSupplier(Map<String,String> map, int key) {
         return (()-> {
         	int bucket = key % stripedLock.size();
             Lock lock = stripedLock.get(bucket);
@@ -31,7 +31,7 @@ public class StripedLock extends ConcurrentAccessExperiment {
         });
     }
 
-    protected synchronized Supplier<?> getSupplier(Map<String,String> map, int key) {
+    protected Supplier<?> getSupplier(Map<String,String> map, int key) {
         return (()-> {
         	int bucket = key % stripedLock.size();
             Lock lock = stripedLock.get(bucket);