diff --git a/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonempty/ReturnFirstNonEmptyOptionalUnitTest.java b/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonempty/ReturnFirstNonEmptyOptionalUnitTest.java
index f2ea8f74e3..b05e0e2d34 100644
--- a/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonempty/ReturnFirstNonEmptyOptionalUnitTest.java
+++ b/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonempty/ReturnFirstNonEmptyOptionalUnitTest.java
@@ -21,9 +21,9 @@ public class ReturnFirstNonEmptyOptionalUnitTest {
     @Test
     void givenListOfOptionals_whenStreaming_thenReturnFirstNonEmpty() {
         Optional<String> object = optionals.stream()
-            .filter(Optional::isPresent)
-            .map(Optional::get)
-            .findFirst();
+          .filter(Optional::isPresent)
+          .map(Optional::get)
+          .findFirst();
 
         assertThat(object).contains("first non empty");
     }
diff --git a/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonnull/ReturnFirstNonNullLazyEvaluateUnitTest.java b/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonnull/ReturnFirstNonNullLazyEvaluateUnitTest.java
index 649e5f4299..fff348052a 100644
--- a/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonnull/ReturnFirstNonNullLazyEvaluateUnitTest.java
+++ b/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonnull/ReturnFirstNonNullLazyEvaluateUnitTest.java
@@ -48,9 +48,9 @@ public class ReturnFirstNonNullLazyEvaluateUnitTest {
     @Test
     void givenChainOfMethods_whenUsingSupplierInterface_thenLazilyEvaluateMethodsUntilFirstNonNull() {
         Optional<String> object = Stream.<Supplier<String>> of(spy::methodA, spy::methodB, spy::methodC)
-            .map(Supplier::get)
-            .filter(Objects::nonNull)
-            .findFirst();
+          .map(Supplier::get)
+          .filter(Objects::nonNull)
+          .findFirst();
 
         assertThat(object).contains("first non null");
         verify(spy, times(1)).methodA();
diff --git a/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonnull/ReturnFirstNonNullUnitTest.java b/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonnull/ReturnFirstNonNullUnitTest.java
index aae775997d..e7bb4d399f 100644
--- a/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonnull/ReturnFirstNonNullUnitTest.java
+++ b/core-java-modules/core-java-lang-6/src/test/java/com/baeldung/returnfirstnonnull/ReturnFirstNonNullUnitTest.java
@@ -28,8 +28,8 @@ public class ReturnFirstNonNullUnitTest {
     @Test
     void givenListOfObjects_whenFilterIsLambdaNullCheck_thenReturnFirstNonNull() {
         Optional<String> object = objects.stream()
-            .filter(o -> o != null)
-            .findFirst();
+          .filter(o -> o != null)
+          .findFirst();
 
         assertThat(object).contains("first non null");
     }
@@ -37,8 +37,8 @@ public class ReturnFirstNonNullUnitTest {
     @Test
     void givenListOfObjects_whenFilterIsMethodRefNullCheck_thenReturnFirstNonNull() {
         Optional<String> object = objects.stream()
-            .filter(Objects::nonNull)
-            .findFirst();
+          .filter(Objects::nonNull)
+          .findFirst();
 
         assertThat(object).contains("first non null");
     }