(Sonar) Fixed finding: "Utility classes should not have public constructors"

src/main/java/com/javaguides/strings/convertions/fromstring/ConvertStringToBooleanExamples.java

@@ -6,6 +6,9 @@
  *
  */
 public class ConvertStringToBooleanExamples {
+	private ConvertStringToBooleanExamples() {
+	}
+
 	public static void main(String[] args) {
 		// Convert using Long.parseLong()
 		String numberAsString = "true";

src/main/java/com/javaguides/strings/convertions/fromstring/ConvertStringToByteExamples.java

@@ -9,6 +9,9 @@
  *
  */
 public class ConvertStringToByteExamples {
+	private ConvertStringToByteExamples() {
+	}
+
 	public static void main(String[] args) {
 		// Convert using IByte.parseByte
 		String numberAsString = "100";

src/main/java/com/javaguides/strings/convertions/fromstring/ConvertStringToCharacterExamples.java

@@ -1,6 +1,9 @@
 package com.javaguides.strings.convertions.fromstring;
 
 public class ConvertStringToCharacterExamples {
+	private ConvertStringToCharacterExamples() {
+	}
+
 	public static void main(String[] args) {
 
 	}

src/main/java/com/javaguides/strings/convertions/fromstring/ConvertStringToDoupleExamples.java

@@ -9,6 +9,9 @@
  *
  */
 public class ConvertStringToDoupleExamples {
+	private ConvertStringToDoupleExamples() {
+	}
+
 	public static void main(String[] args) {
 		// Convert using Double.parseDouble()
 		String str = "153.25";

src/main/java/com/javaguides/strings/convertions/fromstring/ConvertStringToFloatExamples.java

@@ -9,6 +9,9 @@
  *
  */
 public class ConvertStringToFloatExamples {
+	private ConvertStringToFloatExamples() {
+	}
+
 	public static void main(String[] args) {
 		// Convert using Float.parseFloat()
 		String numberAsString = "153.25f";

src/main/java/com/javaguides/strings/convertions/fromstring/ConvertStringToIntegerExamples.java

@@ -9,6 +9,9 @@
  *
  */
 public class ConvertStringToIntegerExamples {
+	private ConvertStringToIntegerExamples() {
+	}
+
 	public static void main(String[] args) {
 		// Convert using Integer.parseInt()
 		String str = "1234";