Extract a Random instance to a variable (#1942)

core-java/src/main/java/com/baeldung/string/StringHelper.java

@@ -2,23 +2,23 @@ package com.baeldung.string;
 
 import java.util.Optional;
 
-public class StringHelper {
-    public static String removeLastChar(String s) {
+class StringHelper {
+    static String removeLastChar(String s) {
         return (s == null || s.length() == 0) ? s : (s.substring(0, s.length() - 1));
     }
 
-    public static String removeLastCharRegex(String s) {
+    static String removeLastCharRegex(String s) {
         return (s == null) ? s : s.replaceAll(".$", "");
     }
 
-    public static String removeLastCharOptional(String s) {
+    static String removeLastCharOptional(String s) {
         return Optional.ofNullable(s)
             .filter(str -> str.length() != 0)
             .map(str -> str.substring(0, str.length() - 1))
             .orElse(s);
     }
 
-    public static String removeLastCharRegexOptional(String s) {
+    static String removeLastCharRegexOptional(String s) {
         return Optional.ofNullable(s)
             .map(str -> str.replaceAll(".$", ""))
             .orElse(s);

core-java/src/test/java/org/baeldung/java/JavaRandomUnitTest.java

@@ -167,9 +167,11 @@ public class JavaRandomUnitTest {
         final int leftLimit = 97; // letter 'a'
         final int rightLimit = 122; // letter 'z'
         final int targetStringLength = 10;
+        final Random random = new Random();
         final StringBuilder buffer = new StringBuilder(targetStringLength);
+
         for (int i = 0; i < targetStringLength; i++) {
-            final int randomLimitedInt = leftLimit + (int) (new Random().nextFloat() * (rightLimit - leftLimit + 1));
+            final int randomLimitedInt = leftLimit + (int) (random.nextFloat() * (rightLimit - leftLimit + 1));
             buffer.append((char) randomLimitedInt);
         }
         final String generatedString = buffer.toString();