diff --git a/libraries/src/main/java/com/baeldung/jdeffered/FilterDemo.java b/libraries/src/main/java/com/baeldung/jdeffered/FilterDemo.java
index fc33824b6f..ec2c52d3b5 100644
--- a/libraries/src/main/java/com/baeldung/jdeffered/FilterDemo.java
+++ b/libraries/src/main/java/com/baeldung/jdeffered/FilterDemo.java
@@ -4,25 +4,21 @@ import org.jdeferred.Deferred;
 import org.jdeferred.Promise;
 import org.jdeferred.impl.DeferredObject;
 
-public class FilterDemo {
+class FilterDemo {
 
-    static String modifiedMsg;
+    private static String modifiedMsg;
     
-    public static String filter(String msg) {
+    static String filter(String msg) {
         
-        Deferred<String, ?, ?> d = new DeferredObject<String, Object, Object>();
+        Deferred<String, ?, ?> d = new DeferredObject<>();
         Promise<String, ?, ?> p = d.promise();
         Promise<String, ?, ?> filtered = p.then((result) -> {
             modifiedMsg = "Hello " + result;
         });
 
-        filtered.done((result) -> {
-            System.out.println("filtering done");
-        });
+        filtered.done(r -> System.out.println("filtering done"));
 
         d.resolve(msg);
         return modifiedMsg;
-        
     }
-
 }
diff --git a/libraries/src/main/java/com/baeldung/jdeffered/PipeDemo.java b/libraries/src/main/java/com/baeldung/jdeffered/PipeDemo.java
index f3c72f1847..95250cff76 100644
--- a/libraries/src/main/java/com/baeldung/jdeffered/PipeDemo.java
+++ b/libraries/src/main/java/com/baeldung/jdeffered/PipeDemo.java
@@ -5,35 +5,31 @@ import org.jdeferred.DonePipe;
 import org.jdeferred.Promise;
 import org.jdeferred.impl.DeferredObject;
 
-public class PipeDemo {
+class PipeDemo {
 
-    public static enum Result {
+    public enum Result {
         SUCCESS, FAILURE
     };
 
-    static Result status;
+    private static Result status;
 
-    public static Result validate(int num) {
-        Deferred<Integer, ?, ?> d = new DeferredObject<Integer, Object, Object>();
+    static Result validate(int num) {
+        Deferred<Integer, ?, ?> d = new DeferredObject<>();
         Promise<Integer, ?, ?> p = d.promise();
 
-        p.then(new DonePipe<Integer, Integer, Exception, Void>() {
-            public Deferred<Integer, Exception, Void> pipeDone(Integer result) {
-                if (result < 90) {
-                    return new DeferredObject<Integer, Exception, Void>().resolve(result);
-                } else {
-                    return new DeferredObject<Integer, Exception, Void>().reject(new Exception("Unacceptable value"));
-                }
+        p.then((DonePipe<Integer, Integer, Exception, Void>) result -> {
+            if (result < 90) {
+                return new DeferredObject<Integer, Exception, Void>()
+                  .resolve(result);
+            } else {
+                return new DeferredObject<Integer, Exception, Void>()
+                  .reject(new Exception("Unacceptable value"));
             }
-        }).done((result) -> {
-            status = Result.SUCCESS;
-        }).fail((result) -> {
-            status = Result.FAILURE;
-        });
+        }).done(r -> status = Result.SUCCESS)
+          .fail(r -> status = Result.FAILURE);
 
         d.resolve(num);
 
         return status;
     }
-
 }
diff --git a/libraries/src/main/java/com/baeldung/jdeffered/PromiseDemo.java b/libraries/src/main/java/com/baeldung/jdeffered/PromiseDemo.java
index 7e38afc3ac..2a9f83dc35 100644
--- a/libraries/src/main/java/com/baeldung/jdeffered/PromiseDemo.java
+++ b/libraries/src/main/java/com/baeldung/jdeffered/PromiseDemo.java
@@ -4,22 +4,17 @@ import org.jdeferred.Deferred;
 import org.jdeferred.Promise;
 import org.jdeferred.impl.DeferredObject;
 
-public class PromiseDemo {
+class PromiseDemo {
 
-    public static void startJob(String jobName) {
+    static void startJob(String jobName) {
 
-        Deferred<String, String, String> deferred = new DeferredObject<String, String, String>();
+        Deferred<String, String, String> deferred = new DeferredObject<>();
         Promise<String, String, String> promise = deferred.promise();
 
-        promise.done((result) -> {
-            System.out.println("Job done");
-        }).fail((rejection) -> {
-            System.out.println("Job fail");
-        }).progress((progress) -> {
-            System.out.println("Job is in progress");
-        }).always((state, result, rejection) -> {
-            System.out.println("Job execution started");
-        });
+        promise.done(result -> System.out.println("Job done"))
+          .fail(rejection -> System.out.println("Job fail"))
+          .progress(progress -> System.out.println("Job is in progress"))
+          .always((state, result, rejection) -> System.out.println("Job execution started"));
 
         deferred.resolve(jobName);
         // deferred.notify("");
diff --git a/libraries/src/main/java/com/baeldung/jdeffered/ThreadSafeDemo.java b/libraries/src/main/java/com/baeldung/jdeffered/ThreadSafeDemo.java
index ae9be964d3..22fd51ed92 100644
--- a/libraries/src/main/java/com/baeldung/jdeffered/ThreadSafeDemo.java
+++ b/libraries/src/main/java/com/baeldung/jdeffered/ThreadSafeDemo.java
@@ -10,13 +10,11 @@ public class ThreadSafeDemo {
 
     public static void task() {
         DeferredManager dm = new DefaultDeferredManager();
-        Deferred<String, String, String> deferred = new DeferredObject<String, String, String>();
+        Deferred<String, String, String> deferred = new DeferredObject<>();
         Promise<String, String, String> p1 = deferred.promise();
-        Promise<String, String, String> p = dm.when(p1).done((result) -> {
-            System.out.println("done");
-        }).fail((result) -> {
-            System.out.println("fail");
-        });
+        Promise<String, String, String> p = dm.when(p1)
+          .done(r -> System.out.println("done"))
+          .fail(r -> System.out.println("fail"));
 
         synchronized (p) {
             while (p.isPending()) {
diff --git a/libraries/src/main/java/com/baeldung/jdeffered/manager/DeferredManagerDemo.java b/libraries/src/main/java/com/baeldung/jdeffered/manager/DeferredManagerDemo.java
index 65a720cc3f..d37a62e309 100644
--- a/libraries/src/main/java/com/baeldung/jdeffered/manager/DeferredManagerDemo.java
+++ b/libraries/src/main/java/com/baeldung/jdeffered/manager/DeferredManagerDemo.java
@@ -6,10 +6,10 @@ import org.jdeferred.Promise;
 import org.jdeferred.impl.DefaultDeferredManager;
 import org.jdeferred.impl.DeferredObject;
 
-public class DeferredManagerDemo {
+class DeferredManagerDemo {
 
     public static void initiate() {
-        Deferred<String, String, String> deferred = new DeferredObject<String, String, String>();
+        Deferred<String, String, String> deferred = new DeferredObject<>();
         DeferredManager dm = new DefaultDeferredManager();
         Promise<String, String, String> p1 = deferred.promise(), p2 = deferred.promise(), p3 = deferred.promise();
         dm.when(p1, p2, p3).done((result) -> {
@@ -19,5 +19,4 @@ public class DeferredManagerDemo {
         });
         deferred.resolve("Hello Baeldung");
     }
-
 }
diff --git a/libraries/src/main/java/com/baeldung/jdeffered/manager/DeferredManagerWithExecutorDemo.java b/libraries/src/main/java/com/baeldung/jdeffered/manager/DeferredManagerWithExecutorDemo.java
index e4669aab06..2abe9bc10f 100644
--- a/libraries/src/main/java/com/baeldung/jdeffered/manager/DeferredManagerWithExecutorDemo.java
+++ b/libraries/src/main/java/com/baeldung/jdeffered/manager/DeferredManagerWithExecutorDemo.java
@@ -9,19 +9,16 @@ import org.jdeferred.Promise;
 import org.jdeferred.impl.DefaultDeferredManager;
 import org.jdeferred.impl.DeferredObject;
 
-public class DeferredManagerWithExecutorDemo {
+class DeferredManagerWithExecutorDemo {
 
     public static void initiate() {
         ExecutorService executor = Executors.newFixedThreadPool(10);
-        Deferred<String, String, String> deferred = new DeferredObject<String, String, String>();
+        Deferred<String, String, String> deferred = new DeferredObject<>();
         DeferredManager dm = new DefaultDeferredManager(executor);
         Promise<String, String, String> p1 = deferred.promise(), p2 = deferred.promise(), p3 = deferred.promise();
-        dm.when(p1, p2, p3).done((result) -> {
-            System.out.println("done");
-        }).fail((result) -> {
-            System.out.println("fail");
-        });
+        dm.when(p1, p2, p3)
+          .done(r -> System.out.println("done"))
+          .fail(r -> System.out.println("fail"));
         deferred.resolve("done");
     }
-
 }
diff --git a/libraries/src/main/java/com/baeldung/jdeffered/manager/SimpleDeferredManagerDemo.java b/libraries/src/main/java/com/baeldung/jdeffered/manager/SimpleDeferredManagerDemo.java
index fc58aa40a2..dc2e82495f 100644
--- a/libraries/src/main/java/com/baeldung/jdeffered/manager/SimpleDeferredManagerDemo.java
+++ b/libraries/src/main/java/com/baeldung/jdeffered/manager/SimpleDeferredManagerDemo.java
@@ -3,17 +3,12 @@ package com.baeldung.jdeffered.manager;
 import org.jdeferred.DeferredManager;
 import org.jdeferred.impl.DefaultDeferredManager;
 
-public class SimpleDeferredManagerDemo {
+class SimpleDeferredManagerDemo {
 
     public static void initiate() {
         DeferredManager dm = new DefaultDeferredManager();
-        dm.when(() -> {
-            return 1;
-        }).done((result) -> {
-            System.out.println("done");
-        }).fail((e) -> {
-            e.printStackTrace();
-        });
+        dm.when(() -> 1)
+          .done(r -> System.out.println("done"))
+          .fail(Throwable::printStackTrace);
     }
-
 }
diff --git a/libraries/src/test/java/com/baeldung/jdeffered/AppTest.java b/libraries/src/test/java/com/baeldung/jdeffered/AppTest.java
index b48c9c2652..97b20cda57 100644
--- a/libraries/src/test/java/com/baeldung/jdeffered/AppTest.java
+++ b/libraries/src/test/java/com/baeldung/jdeffered/AppTest.java
@@ -1,8 +1,7 @@
 package com.baeldung.jdeffered;
 
-import org.junit.Test;
-
 import com.baeldung.jdeffered.PipeDemo.Result;
+import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;
 
@@ -24,5 +23,4 @@ public class AppTest {
         Result result = PipeDemo.validate(80);
         assertEquals(result, Result.SUCCESS);
     }
-
 }