diff --git a/src/main/java/io/github/diegourban/algorithms/datastructure/array/ArrayUtils.java b/src/main/java/io/github/diegourban/algorithms/datastructure/array/ArrayUtils.java
index 29b9eca..d5eb583 100644
--- a/src/main/java/io/github/diegourban/algorithms/datastructure/array/ArrayUtils.java
+++ b/src/main/java/io/github/diegourban/algorithms/datastructure/array/ArrayUtils.java
@@ -4,6 +4,9 @@
 
 public class ArrayUtils {
 
+    private ArrayUtils() {
+    }
+
     private static Random rand = new Random();
 
     /**
diff --git a/src/main/java/io/github/diegourban/algorithms/math/Combinatorics.java b/src/main/java/io/github/diegourban/algorithms/math/Combinatorics.java
index 5e44baf..9b96a25 100644
--- a/src/main/java/io/github/diegourban/algorithms/math/Combinatorics.java
+++ b/src/main/java/io/github/diegourban/algorithms/math/Combinatorics.java
@@ -4,6 +4,9 @@
 
 public class Combinatorics {
 
+    private Combinatorics() {
+    }
+
     /**
      * Pascal's Triangle
      * <p>
diff --git a/src/main/java/io/github/diegourban/algorithms/math/Geometry.java b/src/main/java/io/github/diegourban/algorithms/math/Geometry.java
index 624f173..8ac86ee 100644
--- a/src/main/java/io/github/diegourban/algorithms/math/Geometry.java
+++ b/src/main/java/io/github/diegourban/algorithms/math/Geometry.java
@@ -4,6 +4,9 @@
 
 public class Geometry {
 
+    private Geometry() {
+    }
+
     private static final double SIMPLE_PI = 3.14;
 
     /**
diff --git a/src/main/java/io/github/diegourban/algorithms/math/Measurement.java b/src/main/java/io/github/diegourban/algorithms/math/Measurement.java
index cf87aa2..f3d5b0e 100644
--- a/src/main/java/io/github/diegourban/algorithms/math/Measurement.java
+++ b/src/main/java/io/github/diegourban/algorithms/math/Measurement.java
@@ -2,6 +2,9 @@
 
 public class Measurement {
 
+    private Measurement() {
+    }
+
     /**
      * Converts miles to kilometers
      *
diff --git a/src/main/java/io/github/diegourban/algorithms/math/NumberTheory.java b/src/main/java/io/github/diegourban/algorithms/math/NumberTheory.java
index b06647b..2295228 100644
--- a/src/main/java/io/github/diegourban/algorithms/math/NumberTheory.java
+++ b/src/main/java/io/github/diegourban/algorithms/math/NumberTheory.java
@@ -7,6 +7,9 @@
  */
 public class NumberTheory {
 
+    private NumberTheory() {
+    }
+
     /**
      * Least common multiple (lcm) of two numbers.
      *
diff --git a/src/main/java/io/github/diegourban/algorithms/math/Numbers.java b/src/main/java/io/github/diegourban/algorithms/math/Numbers.java
index 028a2b4..191182e 100644
--- a/src/main/java/io/github/diegourban/algorithms/math/Numbers.java
+++ b/src/main/java/io/github/diegourban/algorithms/math/Numbers.java
@@ -2,6 +2,9 @@
 
 public class Numbers {
 
+    private Numbers() {
+    }
+
     /**
      * Checks if a number contains a digit
      *
diff --git a/src/main/java/io/github/diegourban/algorithms/math/Statistics.java b/src/main/java/io/github/diegourban/algorithms/math/Statistics.java
index 19eebaf..f156fa8 100644
--- a/src/main/java/io/github/diegourban/algorithms/math/Statistics.java
+++ b/src/main/java/io/github/diegourban/algorithms/math/Statistics.java
@@ -4,6 +4,9 @@
 
 public class Statistics {
 
+    private Statistics() {
+    }
+
     /**
      * An average is the sum of a list of numbers divided by the number of
      * numbers in the list.
diff --git a/src/main/java/io/github/diegourban/algorithms/search/BinarySearch.java b/src/main/java/io/github/diegourban/algorithms/search/BinarySearch.java
index 55a3694..751cb17 100644
--- a/src/main/java/io/github/diegourban/algorithms/search/BinarySearch.java
+++ b/src/main/java/io/github/diegourban/algorithms/search/BinarySearch.java
@@ -5,6 +5,9 @@
  */
 public class BinarySearch {
 
+    private BinarySearch() {
+    }
+
     /**
      * Finds an element in an ordered list
      *
diff --git a/src/main/java/io/github/diegourban/algorithms/string/StringUtils.java b/src/main/java/io/github/diegourban/algorithms/string/StringUtils.java
index 3fc93b5..73b8355 100644
--- a/src/main/java/io/github/diegourban/algorithms/string/StringUtils.java
+++ b/src/main/java/io/github/diegourban/algorithms/string/StringUtils.java
@@ -4,6 +4,9 @@
 
 public class StringUtils {
 
+    private StringUtils() {
+    }
+
     public static boolean isPalindrome(String theString) {
         if (theString == null || theString.isEmpty()) {
             return false;
diff --git a/src/test/java/io/github/diegourban/algorithms/datastructure/array/ArrayUtilsTest.java b/src/test/java/io/github/diegourban/algorithms/datastructure/array/ArrayUtilsTest.java
index b6e75ec..901da00 100644
--- a/src/test/java/io/github/diegourban/algorithms/datastructure/array/ArrayUtilsTest.java
+++ b/src/test/java/io/github/diegourban/algorithms/datastructure/array/ArrayUtilsTest.java
@@ -8,11 +8,6 @@
 
 class ArrayUtilsTest {
 
-    @Test
-    void shouldCreateInstance() {
-        assertThat(new ArrayUtils()).isNotNull();
-    }
-
     @Test
     void shouldNotShuffleSmallArray() {
         int[] array = new int[]{1};
diff --git a/src/test/java/io/github/diegourban/algorithms/math/CombinatoricsTest.java b/src/test/java/io/github/diegourban/algorithms/math/CombinatoricsTest.java
index bc2e815..4290e42 100644
--- a/src/test/java/io/github/diegourban/algorithms/math/CombinatoricsTest.java
+++ b/src/test/java/io/github/diegourban/algorithms/math/CombinatoricsTest.java
@@ -9,11 +9,6 @@
 
 class CombinatoricsTest {
 
-    @Test
-    void shouldCreateInstance() {
-        assertThat(new Combinatorics()).isNotNull();
-    }
-
     @Test
     void shouldCalculateBinomialCoefficient() {
         // invalid inputs
diff --git a/src/test/java/io/github/diegourban/algorithms/math/GeometryTest.java b/src/test/java/io/github/diegourban/algorithms/math/GeometryTest.java
index 0998158..be7b6d2 100644
--- a/src/test/java/io/github/diegourban/algorithms/math/GeometryTest.java
+++ b/src/test/java/io/github/diegourban/algorithms/math/GeometryTest.java
@@ -7,11 +7,6 @@
 
 class GeometryTest {
 
-    @Test
-    void shouldCreateInstance() {
-        assertThat(new Geometry()).isNotNull();
-    }
-
     @Test
     void shouldCalculateDistance() {
         assertThat(Geometry.distance(-2, 1, 1, 5)).isCloseTo(5.0, within(0.1));
diff --git a/src/test/java/io/github/diegourban/algorithms/math/MeasurementTest.java b/src/test/java/io/github/diegourban/algorithms/math/MeasurementTest.java
index fc19842..cc63a5f 100644
--- a/src/test/java/io/github/diegourban/algorithms/math/MeasurementTest.java
+++ b/src/test/java/io/github/diegourban/algorithms/math/MeasurementTest.java
@@ -7,11 +7,6 @@
 
 class MeasurementTest {
 
-    @Test
-    void shouldCreateInstance() {
-        assertThat(new Measurement()).isNotNull();
-    }
-
     @Test
     void shouldConvertMilesToKilometers() {
         assertThat(Measurement.milesToKilometers(1)).isCloseTo(1.609344, within(0.1));
diff --git a/src/test/java/io/github/diegourban/algorithms/math/NumberTheoryTest.java b/src/test/java/io/github/diegourban/algorithms/math/NumberTheoryTest.java
index 83c574f..e87eb68 100644
--- a/src/test/java/io/github/diegourban/algorithms/math/NumberTheoryTest.java
+++ b/src/test/java/io/github/diegourban/algorithms/math/NumberTheoryTest.java
@@ -10,11 +10,6 @@
 
 class NumberTheoryTest {
 
-    @Test
-    void shouldCreateInstance() {
-        assertThat(new NumberTheory()).isNotNull();
-    }
-
     @Test
     void shouldFindLeastCommonMultiplesOfTwoNumbers() {
         assertThat(NumberTheory.lcm(1, 2)).isEqualTo(2);
diff --git a/src/test/java/io/github/diegourban/algorithms/math/NumbersTest.java b/src/test/java/io/github/diegourban/algorithms/math/NumbersTest.java
index 26694df..96f8df2 100644
--- a/src/test/java/io/github/diegourban/algorithms/math/NumbersTest.java
+++ b/src/test/java/io/github/diegourban/algorithms/math/NumbersTest.java
@@ -7,11 +7,6 @@
 
 class NumbersTest {
 
-    @Test
-    void shouldCreateInstance() {
-        assertThat(new Numbers()).isNotNull();
-    }
-
     @Test
     void shouldHandleContainsDigit() {
         assertThat(Numbers.containsDigit(124, 4)).isTrue();
diff --git a/src/test/java/io/github/diegourban/algorithms/math/StatisticsTest.java b/src/test/java/io/github/diegourban/algorithms/math/StatisticsTest.java
index ce79f68..cdfeab2 100644
--- a/src/test/java/io/github/diegourban/algorithms/math/StatisticsTest.java
+++ b/src/test/java/io/github/diegourban/algorithms/math/StatisticsTest.java
@@ -8,11 +8,6 @@
 
 class StatisticsTest {
 
-    @Test
-    void shouldCreateInstance() {
-        assertThat(new Statistics()).isNotNull();
-    }
-
     @Test
     void shouldCalculateMean() {
         assertThat(Statistics.mean(new double[]{})).isCloseTo(0.0, within(0.1));
diff --git a/src/test/java/io/github/diegourban/algorithms/string/StringUtilsTest.java b/src/test/java/io/github/diegourban/algorithms/string/StringUtilsTest.java
index 997048a..be626a8 100644
--- a/src/test/java/io/github/diegourban/algorithms/string/StringUtilsTest.java
+++ b/src/test/java/io/github/diegourban/algorithms/string/StringUtilsTest.java
@@ -8,11 +8,6 @@
 
 class StringUtilsTest {
 
-    @Test
-    void shouldCreateInstance() {
-        assertThat(new StringUtils()).isNotNull();
-    }
-
     @Test
     void shouldConsiderPalindrome() {
         assertThat(StringUtils.isPalindrome("a")).isTrue();