diff --git a/libraries/src/main/java/com/baeldung/awaitility/AsyncService.java b/libraries/src/main/java/com/baeldung/awaitility/AsyncService.java
index 3bc82afaac..adfa3e1fb2 100644
--- a/libraries/src/main/java/com/baeldung/awaitility/AsyncService.java
+++ b/libraries/src/main/java/com/baeldung/awaitility/AsyncService.java
@@ -8,25 +8,23 @@ public class AsyncService {
     private final int DELAY = 1000;
     private final int INIT_DELAY = 2000;
 
-    private AtomicLong value = new AtomicLong(0);
-    private Executor executor = Executors.newFixedThreadPool(4);
+    private final AtomicLong value = new AtomicLong(0);
+    private final Executor executor = Executors.newFixedThreadPool(4);
     private volatile boolean initialized = false;
 
-    public void initialize() {
+    void initialize() {
         executor.execute(() -> {
             sleep(INIT_DELAY);
             initialized = true;
         });
     }
 
-    public boolean isInitialized() {
+    boolean isInitialized() {
         return initialized;
     }
 
-    public void addValue(long val) {
-        if (!isInitialized()) {
-            throw new IllegalStateException("Service is not initialized");
-        }
+    void addValue(long val) {
+        throwIfNotInitialized();
         executor.execute(() -> {
             sleep(DELAY);
             value.addAndGet(val);
@@ -34,9 +32,7 @@ public class AsyncService {
     }
 
     public long getValue() {
-        if (!isInitialized()) {
-            throw new IllegalStateException("Service is not initialized");
-        }
+        throwIfNotInitialized();
         return value.longValue();
     }
 
@@ -47,4 +43,10 @@ public class AsyncService {
             e.printStackTrace();
         }
     }
+
+    private void throwIfNotInitialized() {
+        if (!initialized) {
+            throw new IllegalStateException("Service is not initialized");
+        }
+    }
 }
diff --git a/libraries/src/test/java/com/baeldung/awaitility/AsyncServiceUnitTest.java b/libraries/src/test/java/com/baeldung/awaitility/AsyncServiceUnitTest.java
index 4f07d556b9..677d989fba 100644
--- a/libraries/src/test/java/com/baeldung/awaitility/AsyncServiceUnitTest.java
+++ b/libraries/src/test/java/com/baeldung/awaitility/AsyncServiceUnitTest.java
@@ -1,19 +1,20 @@
 package com.baeldung.awaitility;
 
+import org.awaitility.Awaitility;
+import org.awaitility.Duration;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.TimeUnit;
+
 import static org.awaitility.Awaitility.await;
 import static org.awaitility.Awaitility.fieldIn;
 import static org.awaitility.Awaitility.given;
 import static org.awaitility.proxy.AwaitilityClassProxy.to;
 import static org.hamcrest.Matchers.equalTo;
 
-import java.util.concurrent.Callable;
-import java.util.concurrent.TimeUnit;
-
-import org.awaitility.Awaitility;
-import org.awaitility.Duration;
-import org.junit.Before;
-import org.junit.Test;
-
 public class AsyncServiceUnitTest {
     private AsyncService asyncService;
 
@@ -25,18 +26,18 @@ public class AsyncServiceUnitTest {
     @Test
     public void givenAsyncService_whenInitialize_thenInitOccurs1() {
         asyncService.initialize();
-        Callable<Boolean> isInitialized = () -> asyncService.isInitialized();
+        Callable<Boolean> isInitialized = asyncService::isInitialized;
         await().until(isInitialized);
     }
 
     @Test
     public void givenAsyncService_whenInitialize_thenInitOccurs2() {
         asyncService.initialize();
-        Callable<Boolean> isInitialized = () -> asyncService.isInitialized();
+        Callable<Boolean> isInitialized = asyncService::isInitialized;
         await().atLeast(Duration.ONE_HUNDRED_MILLISECONDS)
-                .atMost(Duration.FIVE_SECONDS)
-                .with().pollInterval(Duration.ONE_HUNDRED_MILLISECONDS)
-                .until(isInitialized);
+          .atMost(Duration.FIVE_SECONDS)
+          .with().pollInterval(Duration.ONE_HUNDRED_MILLISECONDS)
+          .until(isInitialized);
     }
 
     @Test
@@ -46,7 +47,7 @@ public class AsyncServiceUnitTest {
         Awaitility.setDefaultTimeout(Duration.ONE_MINUTE);
 
         asyncService.initialize();
-        await().until(() -> asyncService.isInitialized());
+        await().until(asyncService::isInitialized);
     }
 
     @Test
@@ -59,14 +60,14 @@ public class AsyncServiceUnitTest {
     public void givenAsyncService_whenInitialize_thenInitOccurs3() {
         asyncService.initialize();
         await().until(fieldIn(asyncService)
-                .ofType(boolean.class)
-                .andWithName("initialized"), equalTo(true));
+          .ofType(boolean.class)
+          .andWithName("initialized"), equalTo(true));
     }
 
     @Test
     public void givenValue_whenAddValue_thenValueAdded() {
         asyncService.initialize();
-        await().until(() -> asyncService.isInitialized());
+        await().until(asyncService::isInitialized);
         long value = 5;
         asyncService.addValue(value);
         await().until(asyncService::getValue, equalTo(value));
@@ -76,9 +77,9 @@ public class AsyncServiceUnitTest {
     public void givenAsyncService_whenGetValue_thenExceptionIgnored() {
         asyncService.initialize();
         given().ignoreException(IllegalStateException.class)
-                .await()
-                .atMost(Duration.FIVE_SECONDS)
-                .atLeast(Duration.FIVE_HUNDRED_MILLISECONDS)
-                .until(asyncService::getValue, equalTo(0L));
+          .await()
+          .atMost(Duration.FIVE_SECONDS)
+          .atLeast(Duration.FIVE_HUNDRED_MILLISECONDS)
+          .until(asyncService::getValue, equalTo(0L));
     }
 }