diff --git a/cffu-core/src/main/java/io/foldright/cffu/Cffu.java b/cffu-core/src/main/java/io/foldright/cffu/Cffu.java
index 1f7a826e..f82b3d6c 100644
--- a/cffu-core/src/main/java/io/foldright/cffu/Cffu.java
+++ b/cffu-core/src/main/java/io/foldright/cffu/Cffu.java
@@ -494,7 +494,6 @@ public <U, V> Cffu<V> thenCombineAsync(CompletionStage<? extends U> other,
         return reset0(cf.thenCombineAsync(other, fn, executor));
     }
 
-
     /**
      * Returns a new Cffu that, when this and the other given stage both complete normally,
      * is executed with the two results as arguments to the supplied function.
diff --git a/cffu-core/src/main/java/io/foldright/cffu/CffuFactory.java b/cffu-core/src/main/java/io/foldright/cffu/CffuFactory.java
index 8a51584c..5bd725c0 100644
--- a/cffu-core/src/main/java/io/foldright/cffu/CffuFactory.java
+++ b/cffu-core/src/main/java/io/foldright/cffu/CffuFactory.java
@@ -524,7 +524,6 @@ public <T1, T2, T3, T4> Cffu<Tuple4<T1, T2, T3, T4>> allTupleOf(
         return new0(CompletableFutureUtils.allTupleOf(cf1, cf2, cf3, cf4));
     }
 
-
     /**
      * Returns a new Cffu that is successful when the given four CompletableFutures success.
      * If any of the given CompletableFutures complete exceptionally, then the returned
diff --git a/cffu-core/src/main/java/io/foldright/cffu/CompletableFutureUtils.java b/cffu-core/src/main/java/io/foldright/cffu/CompletableFutureUtils.java
index 69d94383..5cd60c74 100644
--- a/cffu-core/src/main/java/io/foldright/cffu/CompletableFutureUtils.java
+++ b/cffu-core/src/main/java/io/foldright/cffu/CompletableFutureUtils.java
@@ -18,6 +18,7 @@
 
 import static io.foldright.cffu.CffuFactory.toCompletableFutureArray;
 import static java.util.Objects.requireNonNull;
+import static java.util.function.Function.identity;
 
 
 /**
@@ -155,7 +156,6 @@ private static void requireCfsAndEleNonNull(CompletionStage<?>... cfs) {
      * Safer for application code which may reuse the returned list as normal collection.
      */
     @SafeVarargs
-    @SuppressWarnings("unchecked")
     private static <T> List<T> arrayList(T... elements) {
         List<T> ret = new ArrayList<>(elements.length);
         ret.addAll(Arrays.asList(elements));
@@ -176,10 +176,10 @@ private static void fill(CompletionStage[] cfs,
             final CompletionStage cf = cfs[i];
 
             successOrBeIncomplete[i] = cf.toCompletableFuture()
-                    .handle((v, ex) -> ex == null ? cf : incomplete).thenCompose(Function.identity());
+                    .handle((v, ex) -> ex == null ? cf : incomplete).thenCompose(identity());
 
             failedOrBeIncomplete[i] = cf.toCompletableFuture()
-                    .handle((v, ex) -> ex == null ? incomplete : cf).thenCompose(Function.identity());
+                    .handle((v, ex) -> ex == null ? incomplete : cf).thenCompose(identity());
         }
     }
 
@@ -1147,7 +1147,7 @@ public static <T> CompletableFuture<T> exceptionallyAsync(
         // below code is copied from CompletionStage#exceptionallyAsync
         return cf.handle((r, ex) -> (ex == null) ? cf :
                 cf.<T>handleAsync((r1, ex1) -> fn.apply(ex1), executor)
-        ).thenCompose(Function.identity());
+        ).thenCompose(identity());
     }
 
     //# Timeout Control methods
@@ -1215,8 +1215,7 @@ public static <T> CompletableFuture<T> exceptionallyCompose(
 
         requireNonNull(fn, "fn is null");
         // below code is copied from CompletionStage.exceptionallyCompose
-        return cf.handle((r, ex) -> (ex == null) ? cf : fn.apply(ex))
-                .thenCompose(Function.identity());
+        return cf.handle((r, ex) -> (ex == null) ? cf : fn.apply(ex)).thenCompose(identity());
     }
 
     /**
@@ -1252,8 +1251,8 @@ public static <T> CompletableFuture<T> exceptionallyComposeAsync(
         requireNonNull(executor, "executor is null");
         // below code is copied from CompletionStage.exceptionallyComposeAsync
         return cf.handle((r, ex) -> (ex == null) ? cf :
-                cf.handleAsync((r1, ex1) -> fn.apply(ex1), executor).thenCompose(Function.identity())
-        ).thenCompose(Function.identity());
+                cf.handleAsync((r1, ex1) -> fn.apply(ex1), executor).thenCompose(identity())
+        ).thenCompose(identity());
     }
 
     //# Read(explicitly) methods of CompletableFuture
@@ -1466,7 +1465,7 @@ public static <T> CompletionStage<T> minimalCompletionStage(CompletableFuture<T>
         if (IS_JAVA9_PLUS) {
             return cf.minimalCompletionStage();
         }
-        return cf.thenApply(Function.identity());
+        return cf.thenApply(identity());
     }
 
     /**
@@ -1483,7 +1482,7 @@ public static <T> CompletableFuture<T> copy(CompletableFuture<T> cf) {
         if (IS_JAVA9_PLUS) {
             return cf.copy();
         }
-        return cf.thenApply(Function.identity());
+        return cf.thenApply(identity());
     }
 
     /**
diff --git a/cffu-core/src/test/java/io/foldright/cffu/CffuFactoryTest.java b/cffu-core/src/test/java/io/foldright/cffu/CffuFactoryTest.java
index 98ebde99..f47ee250 100644
--- a/cffu-core/src/test/java/io/foldright/cffu/CffuFactoryTest.java
+++ b/cffu-core/src/test/java/io/foldright/cffu/CffuFactoryTest.java
@@ -21,6 +21,7 @@
 import static io.foldright.test_utils.TestUtils.*;
 import static java.util.concurrent.CompletableFuture.completedFuture;
 import static java.util.concurrent.ForkJoinPool.commonPool;
+import static java.util.function.Function.identity;
 import static org.junit.jupiter.api.Assertions.*;
 
 
@@ -44,7 +45,7 @@ void test_completedFuture() throws Exception {
     @Test
     void test_completedStage() throws Exception {
         CompletionStage<Integer> stage = cffuFactory.completedStage(n);
-        CompletionStage<Integer> sa = stage.thenApply(Function.identity());
+        CompletionStage<Integer> sa = stage.thenApply(identity());
 
         assertEquals(n, stage.toCompletableFuture().get());
         assertEquals(n, sa.toCompletableFuture().get());
@@ -72,7 +73,7 @@ void test_failedFuture() throws Exception {
     @Test
     void test_failedStage() throws Exception {
         CompletionStage<Integer> stage = cffuFactory.failedStage(rte);
-        CompletionStage<Integer> sa = stage.thenApply(Function.identity());
+        CompletionStage<Integer> sa = stage.thenApply(identity());
         CompletionStage<Integer> se = stage.exceptionally(throwable -> n);
 
         try {
diff --git a/cffu-core/src/test/java/io/foldright/cffu/CffuTest.java b/cffu-core/src/test/java/io/foldright/cffu/CffuTest.java
index 8d7c3127..56c093c5 100644
--- a/cffu-core/src/test/java/io/foldright/cffu/CffuTest.java
+++ b/cffu-core/src/test/java/io/foldright/cffu/CffuTest.java
@@ -14,6 +14,7 @@
 
 import static io.foldright.cffu.CffuFactoryBuilder.newCffuFactoryBuilder;
 import static io.foldright.test_utils.TestUtils.*;
+import static java.util.function.Function.identity;
 import static org.junit.jupiter.api.Assertions.*;
 
 
@@ -123,9 +124,9 @@ void test_either_success() throws Exception {
         assertNull(failed.acceptEitherSuccessAsync(cf, c).get());
         assertNull(failed.acceptEitherSuccessAsync(cf, c, executorService).get());
 
-        assertEquals(n, failed.applyToEitherSuccess(cf, Function.identity()).get());
-        assertEquals(n, failed.applyToEitherSuccessAsync(cf, Function.identity()).get());
-        assertEquals(n, failed.applyToEitherSuccessAsync(cf, Function.identity(), executorService).get());
+        assertEquals(n, failed.applyToEitherSuccess(cf, identity()).get());
+        assertEquals(n, failed.applyToEitherSuccessAsync(cf, identity()).get());
+        assertEquals(n, failed.applyToEitherSuccessAsync(cf, identity(), executorService).get());
     }
 
     ////////////////////////////////////////
@@ -238,7 +239,6 @@ void test_resetCffuFactory() {
         assertSame(forbidObtrudeMethodsCffuFactory, cf.resetCffuFactory(forbidObtrudeMethodsCffuFactory).cffuFactory());
     }
 
-
     ////////////////////////////////////////////////////////////////////////////////
     //# Getter methods of Cffu properties
     //
diff --git a/cffu-core/src/test/java/io/foldright/cffu/CompletableFutureUtilsTest.java b/cffu-core/src/test/java/io/foldright/cffu/CompletableFutureUtilsTest.java
index e57614e9..3a1b5e90 100644
--- a/cffu-core/src/test/java/io/foldright/cffu/CompletableFutureUtilsTest.java
+++ b/cffu-core/src/test/java/io/foldright/cffu/CompletableFutureUtilsTest.java
@@ -21,6 +21,7 @@
 import static io.foldright.test_utils.TestUtils.*;
 import static java.util.concurrent.CompletableFuture.completedFuture;
 import static java.util.concurrent.ForkJoinPool.commonPool;
+import static java.util.function.Function.identity;
 import static org.junit.jupiter.api.Assertions.*;
 
 
@@ -761,9 +762,9 @@ void test_either() throws Exception {
         assertNull(acceptEitherSuccessAsync(cf_n, incomplete, c).get());
         assertNull(acceptEitherSuccessAsync(cf_n, incomplete, c, executorService).get());
 
-        assertEquals(n, applyToEitherSuccess(cf_n, incomplete, Function.identity()).get());
-        assertEquals(n, applyToEitherSuccessAsync(cf_n, incomplete, Function.identity()).get());
-        assertEquals(n, applyToEitherSuccessAsync(cf_n, incomplete, Function.identity(), executorService).get());
+        assertEquals(n, applyToEitherSuccess(cf_n, incomplete, identity()).get());
+        assertEquals(n, applyToEitherSuccessAsync(cf_n, incomplete, identity()).get());
+        assertEquals(n, applyToEitherSuccessAsync(cf_n, incomplete, identity(), executorService).get());
     }
 
     @Test
@@ -783,9 +784,9 @@ void test_either_success() throws Exception {
         assertNull(acceptEitherSuccessAsync(failed, cf, c).get());
         assertNull(acceptEitherSuccessAsync(failed, cf, c, executorService).get());
 
-        assertEquals(n, applyToEitherSuccess(failed, cf, Function.identity()).get());
-        assertEquals(n, applyToEitherSuccessAsync(failed, cf, Function.identity()).get());
-        assertEquals(n, applyToEitherSuccessAsync(failed, cf, Function.identity(), executorService).get());
+        assertEquals(n, applyToEitherSuccess(failed, cf, identity()).get());
+        assertEquals(n, applyToEitherSuccessAsync(failed, cf, identity()).get());
+        assertEquals(n, applyToEitherSuccessAsync(failed, cf, identity(), executorService).get());
     }
 
     ////////////////////////////////////////////////////////////////////////////////
diff --git a/cffu-core/src/test/java/io/foldright/showcases/CompletableFutureUsageShowcaseTest.kt b/cffu-core/src/test/java/io/foldright/showcases/CompletableFutureUsageShowcaseTest.kt
index c4d17d5f..d8597be6 100644
--- a/cffu-core/src/test/java/io/foldright/showcases/CompletableFutureUsageShowcaseTest.kt
+++ b/cffu-core/src/test/java/io/foldright/showcases/CompletableFutureUsageShowcaseTest.kt
@@ -392,7 +392,6 @@ class CompletableFutureUsageShowcaseTest : FunSpec({
             42
         }.toCompletableFuture().await() shouldBe 42
 
-
         cf.thenApply { it }.handle { _, t ->
             t.shouldBeTypeOf<CompletionException>()
             t.cause shouldBeSameInstanceAs rte
diff --git a/cffu-core/src/test/java/io/foldright/test_utils/TestThreadPoolManager.kt b/cffu-core/src/test/java/io/foldright/test_utils/TestThreadPoolManager.kt
index a610fd49..4b2383ad 100644
--- a/cffu-core/src/test/java/io/foldright/test_utils/TestThreadPoolManager.kt
+++ b/cffu-core/src/test/java/io/foldright/test_utils/TestThreadPoolManager.kt
@@ -86,12 +86,10 @@ fun shutdownExecutorService(vararg executors: ExecutorService) {
     }
 }
 
-
 ////////////////////////////////////////////////////////////////////////////////
 // executors for kotest
 ////////////////////////////////////////////////////////////////////////////////
 
-
 val testThreadPoolExecutor: ExecutorService =
     createThreadPool("CompletableFutureUseTest_ThreadPool")
 
diff --git a/cffu-core/src/test/java/io/foldright/test_utils/TestUtils.kt b/cffu-core/src/test/java/io/foldright/test_utils/TestUtils.kt
index 48fc340e..181b2e93 100644
--- a/cffu-core/src/test/java/io/foldright/test_utils/TestUtils.kt
+++ b/cffu-core/src/test/java/io/foldright/test_utils/TestUtils.kt
@@ -499,7 +499,6 @@ private fun <T> Cffu<T>.shouldNotMinCffu(recursive: Boolean = false) {
 
     if (recursive) newIncompleteFuture<T>().shouldNotMinCffu()
 
-
     ////////////////////////////////////////////////////////////
     // Cffu specified methods
     ////////////////////////////////////////////////////////////
diff --git a/cffu-kotlin/src/main/java/io/foldright/cffu/kotlin/CompletableFutureExtensions.kt b/cffu-kotlin/src/main/java/io/foldright/cffu/kotlin/CompletableFutureExtensions.kt
index 83e34499..049b65c6 100644
--- a/cffu-kotlin/src/main/java/io/foldright/cffu/kotlin/CompletableFutureExtensions.kt
+++ b/cffu-kotlin/src/main/java/io/foldright/cffu/kotlin/CompletableFutureExtensions.kt
@@ -73,7 +73,6 @@ fun Collection<CompletionStage<*>>.allOfCompletableFuture(): CompletableFuture<V
 fun Array<out CompletionStage<*>>.allOfCompletableFuture(): CompletableFuture<Void> =
     CompletableFuture.allOf(*(this as Array<CompletionStage<Any>>).toCompletableFuture())
 
-
 /**
  * Returns a new CompletableFuture that is successful when all the given CompletableFutures success,
  * the results(`CompletableFuture<Void>`) of the given CompletableFutures are not reflected in the returned CompletableFuture,
diff --git a/cffu-kotlin/src/test/java/io/foldright/cffu/test/CffuExtensionsTest.kt b/cffu-kotlin/src/test/java/io/foldright/cffu/test/CffuExtensionsTest.kt
index abc74a26..5e32aed4 100644
--- a/cffu-kotlin/src/test/java/io/foldright/cffu/test/CffuExtensionsTest.kt
+++ b/cffu-kotlin/src/test/java/io/foldright/cffu/test/CffuExtensionsTest.kt
@@ -380,7 +380,6 @@ class CffuExtensionsTest : FunSpec({
         ).anyOfSuccessCffu(testCffuFactory).await() shouldBe 42
     }
 
-
     val cffuFactoryForOptional = newCffuFactoryBuilder(Executors.newCachedThreadPool()).build()
     fun assertCffuFactoryForOptional(cffu: Cffu<*>) {
         cffu.cffuFactory() shouldBeSameInstanceAs cffuFactoryForOptional
diff --git a/cffu-kotlin/src/test/java/io/foldright/cffu/test/CompletableFutureExtensionsTest.kt b/cffu-kotlin/src/test/java/io/foldright/cffu/test/CompletableFutureExtensionsTest.kt
index 762b8709..4b97bef6 100644
--- a/cffu-kotlin/src/test/java/io/foldright/cffu/test/CompletableFutureExtensionsTest.kt
+++ b/cffu-kotlin/src/test/java/io/foldright/cffu/test/CompletableFutureExtensionsTest.kt
@@ -24,7 +24,7 @@ import java.util.concurrent.TimeUnit
 import java.util.concurrent.TimeoutException
 import java.util.function.BiConsumer
 import java.util.function.Consumer
-import java.util.function.Function
+import java.util.function.Function.identity
 
 class CompletableFutureExtensionsTest : FunSpec({
     test("allOf*") {
@@ -326,9 +326,9 @@ class CompletableFutureExtensionsTest : FunSpec({
         failed.acceptEitherSuccessAsync(cf, c).get().shouldBeNull()
         failed.acceptEitherSuccessAsync(cf, c, testThreadPoolExecutor).get().shouldBeNull()
 
-        failed.applyToEitherSuccess(cf, Function.identity()).get() shouldBe n
-        failed.applyToEitherSuccessAsync(cf, Function.identity()).get() shouldBe n
-        failed.applyToEitherSuccessAsync(cf, Function.identity(), testThreadPoolExecutor).get() shouldBe n
+        failed.applyToEitherSuccess(cf, identity()).get() shouldBe n
+        failed.applyToEitherSuccessAsync(cf, identity()).get() shouldBe n
+        failed.applyToEitherSuccessAsync(cf, identity(), testThreadPoolExecutor).get() shouldBe n
     }
 
     ////////////////////////////////////////////////////////////////////////////////