diff --git a/core-java-modules/core-java-security/src/main/java/com/baeldung/folding/FoldingHash.java b/core-java-modules/core-java-security/src/main/java/com/baeldung/folding/FoldingHash.java
index 3cb0d55ca7..0ea128c1d9 100644
--- a/core-java-modules/core-java-security/src/main/java/com/baeldung/folding/FoldingHash.java
+++ b/core-java-modules/core-java-security/src/main/java/com/baeldung/folding/FoldingHash.java
@@ -15,11 +15,12 @@ import java.util.stream.IntStream;
 public class FoldingHash {
 
     /**
-     * Calculate the hash value of a given string 
-     * @param str
-     * @param groupSize
-     * @param maxValue
-     * @return
+     * Calculate the hash value of a given string.
+     * 
+     * @param str Assume it is not null
+     * @param groupSize the group size in the folding technique
+     * @param maxValue defines a max value that the hash may acquire (exclusive)     
+     * @return integer value from 0 (inclusive) to maxValue (exclusive)
      */
     public int hash(String str, int groupSize, int maxValue) {
         final int[] codes = this.toAsciiCodes(str);
@@ -37,9 +38,9 @@ public class FoldingHash {
      * If the original array has not enough elements, the returning array will contain 
      * element from the offset till the end of the original array.
      *  
-     * @param numbers
-     * @param offset
-     * @param length
+     * @param numbers original array. Assume it is not null.
+     * @param offset index of the element to start from. Assume it is less than the size of the array 
+     * @param length max size of the resulting array
      * @return
      */
     public int[] extract(int[] numbers, int offset, int length) {
@@ -53,9 +54,9 @@ public class FoldingHash {
     }
 
     /**
-     * Concatenate the numbers into a single number.
+     * Concatenate the numbers into a single number as if they were strings.
      * Assume that the procedure does not suffer from the overflow.
-     * @param numbers
+     * @param numbers integers to concatenate
      * @return
      */
     public int concatenate(int[] numbers) {
@@ -66,8 +67,8 @@ public class FoldingHash {
     }
 
     /**
-     * Convert the string into its characters' ascii codes.
-     * @param str
+     * Convert the string into its characters' ASCII codes.
+     * @param str input string
      * @return
      */
     private int[] toAsciiCodes(String str) {
diff --git a/core-java-modules/core-java-security/src/main/java/com/baeldung/folding/Main.java b/core-java-modules/core-java-security/src/main/java/com/baeldung/folding/Main.java
index dec5b4850a..3b055a0dbe 100644
--- a/core-java-modules/core-java-security/src/main/java/com/baeldung/folding/Main.java
+++ b/core-java-modules/core-java-security/src/main/java/com/baeldung/folding/Main.java
@@ -7,11 +7,11 @@ package com.baeldung.folding;
  *
  */
 public class Main {
+
     public static void main(String... arg) {
         FoldingHash hasher = new FoldingHash();
         final String str = "Java language";
         System.out.println(hasher.hash(str, 2, 100_000));
         System.out.println(hasher.hash(str, 3, 1_000));
     }
-
 }
diff --git a/core-java-modules/core-java-security/src/test/java/com/baeldung/folding/FoldingHashUnitTest.java b/core-java-modules/core-java-security/src/test/java/com/baeldung/folding/FoldingHashUnitTest.java
index b8e9adf435..43e33d8378 100644
--- a/core-java-modules/core-java-security/src/test/java/com/baeldung/folding/FoldingHashUnitTest.java
+++ b/core-java-modules/core-java-security/src/test/java/com/baeldung/folding/FoldingHashUnitTest.java
@@ -14,44 +14,41 @@ public class FoldingHashUnitTest {
         final int value = hasher.hash("Java language", 2, 100_000);
         assertEquals(value, 48933);
     }
-    
-    
+
     @Test
     public void givenStringVaJaLanguage_whenSize2Capacity100000_thenSameAsJavaLanguage() throws Exception {
         final FoldingHash hasher = new FoldingHash();
         final int java = hasher.hash("Java language", 2, 100_000);
         final int vaja = hasher.hash("vaJa language", 2, 100_000);
         assertTrue(java == vaja);
-    }    
-
+    }
 
     @Test
     public void givenSingleElementArray_whenOffset0Size2_thenSingleElement() throws Exception {
         final FoldingHash hasher = new FoldingHash();
-        final int[] value = hasher.extract(new int[] {5}, 0, 2);
-        assertArrayEquals(new int[] {5}, value);
+        final int[] value = hasher.extract(new int[] { 5 }, 0, 2);
+        assertArrayEquals(new int[] { 5 }, value);
     }
-    
+
     @Test
     public void givenFiveElementArray_whenOffset0Size3_thenFirstThreeElements() throws Exception {
         final FoldingHash hasher = new FoldingHash();
-        final int[] value = hasher.extract(new int[] {1, 2, 3, 4, 5}, 0, 3);
-        assertArrayEquals(new int[] {1, 2, 3}, value);
+        final int[] value = hasher.extract(new int[] { 1, 2, 3, 4, 5 }, 0, 3);
+        assertArrayEquals(new int[] { 1, 2, 3 }, value);
     }
 
     @Test
     public void givenFiveElementArray_whenOffset1Size2_thenTwoElements() throws Exception {
         final FoldingHash hasher = new FoldingHash();
-        final int[] value = hasher.extract(new int[] {1, 2, 3, 4, 5}, 1, 2);
-        assertArrayEquals(new int[] {2, 3}, value);
+        final int[] value = hasher.extract(new int[] { 1, 2, 3, 4, 5 }, 1, 2);
+        assertArrayEquals(new int[] { 2, 3 }, value);
     }
 
     @Test
     public void givenFiveElementArray_whenOffset2SizeTooBig_thenElementsToTheEnd() throws Exception {
         final FoldingHash hasher = new FoldingHash();
-        final int[] value = hasher.extract(new int[] {1, 2, 3, 4, 5}, 2, 2000);
-        assertArrayEquals(new int[] {3, 4, 5}, value);
+        final int[] value = hasher.extract(new int[] { 1, 2, 3, 4, 5 }, 2, 2000);
+        assertArrayEquals(new int[] { 3, 4, 5 }, value);
     }
-    
-    
+
 }