diff --git a/libraries/pom.xml b/libraries/pom.xml
index 936e86873d..fb1f1cd1b6 100644
--- a/libraries/pom.xml
+++ b/libraries/pom.xml
@@ -942,7 +942,7 @@
         <yarg.version>2.0.4</yarg.version>
         <mbassador.version>1.3.1</mbassador.version>
         <jdeferred.version>1.2.6</jdeferred.version>
-        <functionaljava.version>4.7</functionaljava.version>
+        <functionaljava.version>4.8.1</functionaljava.version>
         <jgrapht.version>1.0.1</jgrapht.version>
         <docx4j.version>3.3.5</docx4j.version>
         <jaxb-api.version>2.1</jaxb-api.version>
diff --git a/libraries/src/test/java/com/baeldung/fj/FunctionalJavaUnitTest.java b/libraries/src/test/java/com/baeldung/fj/FunctionalJavaUnitTest.java
index d62a115abd..aa06ba4eb9 100644
--- a/libraries/src/test/java/com/baeldung/fj/FunctionalJavaUnitTest.java
+++ b/libraries/src/test/java/com/baeldung/fj/FunctionalJavaUnitTest.java
@@ -1,79 +1,122 @@
-package com.baeldung.fj;
-
-import static org.junit.Assert.assertEquals;
-
-import org.junit.Test;
-
-import fj.F;
-import fj.data.Array;
-import fj.data.List;
-import fj.data.Option;
-import fj.function.Characters;
-import fj.function.Integers;
-
-public class FunctionalJavaUnitTest {
-
-    public static final F<Integer, Boolean> isEven = i -> i % 2 == 0;
-
-    @Test
-    public void calculateEvenNumbers_givenIntList_returnTrue() {
-        List<Integer> fList = List.list(3, 4, 5, 6);
-        List<Boolean> evenList = fList.map(isEven);
-        List<Boolean> evenListTrueResult = List.list(false, true, false, true);
-        List<Boolean> evenListFalseResult = List.list(true, false, false, true);
-        assertEquals(evenList.equals(evenListTrueResult), true);
-        assertEquals(evenList.equals(evenListFalseResult), false);
-    }
-
-    @Test
-    public void mapList_givenIntList_returnResult() {
-        List<Integer> fList = List.list(3, 4, 5, 6);
-        fList = fList.map(i -> i + 100);
-        List<Integer> resultList = List.list(103, 104, 105, 106);
-        List<Integer> falseResultList = List.list(15, 504, 105, 106);
-        assertEquals(fList.equals(resultList), true);
-        assertEquals(fList.equals(falseResultList), false);
-    }
-
-    @Test
-    public void filterList_givenIntList_returnResult() {
-        Array<Integer> array = Array.array(3, 4, 5, 6);
-        Array<Integer> filteredArray = array.filter(Integers.even);
-        Array<Integer> result = Array.array(4, 6);
-        Array<Integer> wrongResult = Array.array(3, 5);
-        assertEquals(filteredArray.equals(result), true);
-        assertEquals(filteredArray.equals(wrongResult), false);
-    }
-
-    @Test
-    public void checkForLowerCase_givenStringArray_returnResult() {
-        Array<String> array = Array.array("Welcome", "To", "baeldung");
-        Array<String> array2 = Array.array("Welcome", "To", "Baeldung");
-        Boolean isExist = array.exists(s -> List.fromString(s).forall(Characters.isLowerCase));
-        Boolean isExist2 = array2.exists(s -> List.fromString(s).forall(Characters.isLowerCase));
-        assertEquals(isExist, true);
-        assertEquals(isExist2, false);
-    }
-
-    @Test
-    public void checkOptions_givenOptions_returnResult() {
-        Option<Integer> n1 = Option.some(1);
-        Option<Integer> n2 = Option.some(2);
-
-        F<Integer, Option<Integer>> f1 = i -> i % 2 == 0 ? Option.some(i + 100) : Option.none();
-
-        Option<Integer> result1 = n1.bind(f1);
-        Option<Integer> result2 = n2.bind(f1);
-
-        assertEquals(result1, Option.none());
-        assertEquals(result2, Option.some(102));
-    }
-
-    @Test
-    public void foldLeft_givenArray_returnResult() {
-        Array<Integer> intArray = Array.array(17, 44, 67, 2, 22, 80, 1, 27);
-        int sum = intArray.foldLeft(Integers.add, 0);
-        assertEquals(sum, 260);
-    }
-
-}
+package com.baeldung.fj;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import fj.F;
+import fj.Show;
+import fj.data.Array;
+import fj.data.List;
+import fj.data.Option;
+import fj.function.Characters;
+import fj.function.Integers;
+
+public class FunctionalJavaUnitTest {
+
+    public static final F<Integer, Boolean> isEven = i -> i % 2 == 0;
+
+    public static final Integer timesTwoRegular(Integer i) {
+        return i * 2;
+    }
+
+    public static final F<Integer, Integer> timesTwo = i -> i * 2;
+
+    public static final F<Integer, Integer> plusOne = i -> i + 1;
+
+    @Test
+    public void multiplyNumbers_givenIntList_returnTrue() {
+        List<Integer> fList = List.list(1, 2, 3, 4);
+        List<Integer> fList1 = fList.map(timesTwo);
+        List<Integer> fList2 = fList.map(i -> i * 2);
+
+        assertEquals(fList1.equals(fList2), true);
+    }
+
+    @Test
+    public void applyMultipleFunctions_givenIntList_returnFalse() {
+        List<Integer> fList = List.list(1, 2, 3, 4);
+        List<Integer> fList1 = fList.map(timesTwo).map(plusOne);
+        Show.listShow(Show.intShow).println(fList1);
+        List<Integer> fList2 = fList.map(plusOne).map(timesTwo);
+        Show.listShow(Show.intShow).println(fList2);
+
+        assertEquals(fList1.equals(fList2), false);
+    }
+
+    @Test
+    public void calculateEvenNumbers_givenIntList_returnTrue() {
+        List<Integer> fList = List.list(3, 4, 5, 6);
+        List<Boolean> evenList = fList.map(isEven);
+        List<Boolean> evenListTrueResult = List.list(false, true, false, true);
+        List<Boolean> evenListFalseResult = List.list(true, false, false, true);
+
+        assertEquals(evenList.equals(evenListTrueResult), true);
+        assertEquals(evenList.equals(evenListFalseResult), false);
+    }
+
+    @Test
+    public void mapList_givenIntList_returnResult() {
+        List<Integer> fList = List.list(3, 4, 5, 6);
+        fList = fList.map(i -> i + 100);
+        List<Integer> resultList = List.list(103, 104, 105, 106);
+        List<Integer> falseResultList = List.list(15, 504, 105, 106);
+
+        assertEquals(fList.equals(resultList), true);
+        assertEquals(fList.equals(falseResultList), false);
+    }
+
+    @Test
+    public void filterList_givenIntList_returnResult() {
+        Array<Integer> array = Array.array(3, 4, 5, 6);
+        Array<Integer> filteredArray = array.filter(isEven);
+        Array<Integer> result = Array.array(4, 6);
+        Array<Integer> wrongResult = Array.array(3, 5);
+
+        assertEquals(filteredArray.equals(result), true);
+        assertEquals(filteredArray.equals(wrongResult), false);
+    }
+
+    @Test
+    public void checkForLowerCase_givenStringArray_returnResult() {
+        Array<String> array = Array.array("Welcome", "To", "baeldung");
+        Array<String> array2 = Array.array("Welcome", "To", "Baeldung");
+        Boolean isExist = array.exists(s -> List.fromString(s).forall(Characters.isLowerCase));
+        Boolean isExist2 = array2.exists(s -> List.fromString(s).forall(Characters.isLowerCase));
+        Boolean isAll = array.forall(s -> List.fromString(s).forall(Characters.isLowerCase));
+
+        assertEquals(isExist, true);
+        assertEquals(isExist2, false);
+        assertEquals(isAll, false);
+    }
+
+    @Test
+    public void checkOptions_givenOptions_returnResult() {
+        Option<Integer> n1 = Option.some(1);
+        Option<Integer> n2 = Option.some(2);
+        Option<Integer> n3 = Option.none();
+
+        F<Integer, Option<Integer>> function = i -> i % 2 == 0 ? Option.some(i + 100) : Option.none();
+
+        Option<Integer> result1 = n1.bind(function);
+        Option<Integer> result2 = n2.bind(function);
+        Option<Integer> result3 = n3.bind(function);
+
+        assertEquals(result1, Option.none());
+        assertEquals(result2, Option.some(102));
+        assertEquals(result3, Option.none());
+    }
+
+    @Test
+    public void foldLeft_givenArray_returnResult() {
+        Array<Integer> intArray = Array.array(17, 44, 67, 2, 22, 80, 1, 27);
+        int sumAll = intArray.foldLeft(Integers.add, 0);
+
+        assertEquals(sumAll, 260);
+
+        int sumEven = intArray.filter(isEven).foldLeft(Integers.add, 0);
+
+        assertEquals(sumEven, 148);
+    }
+
+}