This PR is related to BAEL-7174 (#15712)

* Update pom.xml

Add:        <module>core-java-regex-3</module>

* This commit is related to BAEL-7174

This commit aims to add a new module named "core-java-regex-3" and a new project named "passwordvalidation" to validate passwords using regex.

* Update PasswordValidationUsingRegexUnitTest.java

Change else-if to         assertTrue(matcher.matches());

core-java-modules/core-java-regex-3/README.md

@@ -0,0 +1,3 @@
+### Relevant Articles:
+
+- More articles: [[<-- prev]](/core-java-modules/core-java-regex-2)

core-java-modules/core-java-regex-3/pom.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>core-java-regex-3</artifactId>
+    <name>core-java-regex-3</name>
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.8.1</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+
+</project>

core-java-modules/core-java-regex-3/src/test/java/com/baeldung/passwordvalidation/PasswordValidationUsingRegexUnitTest.java

@@ -0,0 +1,53 @@
+package com.baeldung.passwordvalidation;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class PasswordValidationUsingRegexUnitTest {
+    String password = "Baeldung20@";
+
+    @Test
+    public void givenStringPassword_whenUsingDynamicPasswordValidationRules_thenCheckIfPasswordValid() {
+        boolean result = false;
+        try {
+            if (password != null) {
+                String MIN_LENGHT = "8";
+                String MAX_LENGHT = "20";
+                boolean SPECIAL_CHAR_NEEDED = false;
+
+                String ONE_DIGIT = "(?=.*[0-9])";
+                String LOWER_CASE = "(?=.*[a-z])";
+                String UPPER_CASE = "(?=.*[A-Z])";
+                String SPECIAL_CHAR = SPECIAL_CHAR_NEEDED ? "(?=.*[@#$%^&+=])" : "";
+                String NO_SPACE = "(?=\\S+$)";
+
+                String MIN_MAX_CHAR = ".{" + MIN_LENGHT + "," + MAX_LENGHT + "}";
+                String PATTERN = ONE_DIGIT + LOWER_CASE + UPPER_CASE + SPECIAL_CHAR + NO_SPACE + MIN_MAX_CHAR;
+
+                assertTrue(password.matches(PATTERN));
+            }
+
+        } catch (Exception ex) {
+            ex.printStackTrace();
+            fail("Exception occurred: " + ex.getMessage());
+        }
+    }
+
+    @Test
+    public void givenStringPassword_whenUsingRegulaExpressions_thenCheckIfPasswordValid() {
+
+
+        String regExpn =
+                "^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%^&+=])(?=\\S+$).{8,20}$";
+
+        Pattern pattern = Pattern.compile(regExpn, Pattern.CASE_INSENSITIVE);
+        Matcher matcher = pattern.matcher(password);
+
+        assertTrue(matcher.matches());
+    }
+
+}

core-java-modules/pom.xml

@@ -200,6 +200,7 @@
         <module>core-java-string-operations-7</module>
         <module>core-java-regex</module>
         <module>core-java-regex-2</module>
+        <module>core-java-regex-3</module>
         <module>core-java-uuid</module>
         <module>core-java-collections-maps-6</module>
         <module>core-java-records</module>