diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
new file mode 100644
index 0000000..2f44ced
--- /dev/null
+++ b/.github/workflows/maven.yml
@@ -0,0 +1,29 @@
+# This workflow will build a Java project with Maven, and cache/restore any dependencies to improve the workflow execution time
+# For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-maven
+
+name: Test Case Report
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up JDK 11 Amazon Corretto
+        uses: actions/setup-java@v3
+        with:
+          java-version: '11'
+          distribution: 'corretto'
+          cache: maven
+      - name: Build with Maven
+        run: mvn -B package --file pom.xml
+      - name: Test with Maven
+        run: mvn -B test --file pom.xml
+      
diff --git a/.github/workflows/super-linter.yml b/.github/workflows/super-linter.yml
new file mode 100644
index 0000000..bd14a83
--- /dev/null
+++ b/.github/workflows/super-linter.yml
@@ -0,0 +1,29 @@
+# This workflow executes several linters on changed files based on languages used in your code base whenever
+# you push a code or open a pull request.
+#
+# You can adjust the behavior by modifying this file.
+# For more information, see:
+# https://github.com/github/super-linter
+name: Lint Code Base
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+jobs:
+  run-lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+        with:
+          # Full git history is needed to get a proper list of changed files within `super-linter`
+          fetch-depth: 0
+
+      - name: Lint Code Base
+        uses: github/super-linter@v4
+        env:
+          VALIDATE_ALL_CODEBASE: false
+          DEFAULT_BRANCH: main
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.gitignore b/.gitignore
index 9f91b2d..e9ddf70 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,7 @@ target/
 !**/src/test/**/target/
 
 ### IntelliJ IDEA ###
+.idea/
 .idea/modules.xml
 .idea/jarRepositories.xml
 .idea/compiler.xml
@@ -38,4 +39,5 @@ build/
 .DS_Store
 
 ### SonarLint ###
-.idea/sonarlint/
\ No newline at end of file
+
+!/.idea/sonarlint/
diff --git a/.idea/misc.xml b/.idea/misc.xml
index 4258c62..0bc224b 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -8,7 +8,7 @@
       </list>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_18" default="true" project-jdk-name="18" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" project-jdk-name="18" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>
\ No newline at end of file
diff --git a/.idea/sonarlint/issuestore/4/4/442292b8a7efeabbe4cc176709b833b1792140ec b/.idea/sonarlint/issuestore/4/4/442292b8a7efeabbe4cc176709b833b1792140ec
deleted file mode 100644
index e69de29..0000000
diff --git a/.idea/sonarlint/issuestore/8/a/8a6dae537be9f47878c6964c6ee40cab0ca75e28 b/.idea/sonarlint/issuestore/8/a/8a6dae537be9f47878c6964c6ee40cab0ca75e28
deleted file mode 100644
index e69de29..0000000
diff --git a/.idea/sonarlint/issuestore/index.pb b/.idea/sonarlint/issuestore/index.pb
index ff5edbe..e69de29 100644
--- a/.idea/sonarlint/issuestore/index.pb
+++ b/.idea/sonarlint/issuestore/index.pb
@@ -1,5 +0,0 @@
-
-w
-G.idea/sonarlint/issuestore/e/d/ed67eb178d523a4b3f117dcbe0eda5196367ceec,8\a\8a6dae537be9f47878c6964c6ee40cab0ca75e28
-w
-G.idea/sonarlint/issuestore/4/4/442292b8a7efeabbe4cc176709b833b1792140ec,8\6\863e0292fd7e9b3e74dafd6cc01f73ba76346482
\ No newline at end of file
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index 33f4569..4e9c26f 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -4,11 +4,7 @@
     <option name="autoReloadType" value="SELECTIVE" />
   </component>
   <component name="ChangeListManager">
-    <list default="true" id="b3bac6d6-f8b1-474b-a5e1-72bf67a3867c" name="Changes" comment="add proper test names">
-      <change beforePath="$PROJECT_DIR$/.idea/sonarlint/issuestore/index.pb" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/sonarlint/issuestore/index.pb" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/README.md" beforeDir="false" afterPath="$PROJECT_DIR$/README.md" afterDir="false" />
-    </list>
+    <list default="true" id="b3bac6d6-f8b1-474b-a5e1-72bf67a3867c" name="Changes" comment="add a badge, change name for the workflow" />
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
     <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />
@@ -52,7 +48,18 @@
     &quot;com.intellij.testIntegration.createTest.CreateTestDialog.defaultLibrarySuperClass.JUnit5&quot;: &quot;&quot;,
     &quot;full.screen.before.presentation.mode&quot;: &quot;false&quot;,
     &quot;last_opened_file_path&quot;: &quot;C:/Users/divya/Exercism/java/need-for-speed&quot;,
-    &quot;settings.editor.selected.configurable&quot;: &quot;reference.settingsdialog.IDE.editor.colors.Color Scheme Font&quot;
+    &quot;project.structure.last.edited&quot;: &quot;Project&quot;,
+    &quot;project.structure.proportion&quot;: &quot;0.15&quot;,
+    &quot;project.structure.side.proportion&quot;: &quot;0.0&quot;,
+    &quot;settings.editor.selected.configurable&quot;: &quot;preferences.pluginManager&quot;
+  },
+  &quot;keyToStringList&quot;: {
+    &quot;DatabaseDriversLRU&quot;: [
+      &quot;mysql&quot;
+    ],
+    &quot;com.intellij.ide.scratch.ScratchImplUtil$2/New Scratch File&quot;: [
+      &quot;Markdown&quot;
+    ]
   }
 }</component>
   <component name="RecentsManager">
@@ -157,6 +164,7 @@
       <workItem from="1652622259082" duration="160000" />
       <workItem from="1652631231540" duration="1640000" />
       <workItem from="1652638374278" duration="312000" />
+      <workItem from="1652815591071" duration="2935000" />
     </task>
     <task id="LOCAL-00001" summary="initial commit">
       <created>1652464516513</created>
@@ -277,7 +285,28 @@
       <option name="project" value="LOCAL" />
       <updated>1652633662838</updated>
     </task>
-    <option name="localTasksCounter" value="18" />
+    <task id="LOCAL-00018" summary="change maven target version to 11">
+      <created>1652816083393</created>
+      <option name="number" value="00018" />
+      <option name="presentableId" value="LOCAL-00018" />
+      <option name="project" value="LOCAL" />
+      <updated>1652816083393</updated>
+    </task>
+    <task id="LOCAL-00019" summary="add maven plugins to run junit5 test with maven">
+      <created>1652819174296</created>
+      <option name="number" value="00019" />
+      <option name="presentableId" value="LOCAL-00019" />
+      <option name="project" value="LOCAL" />
+      <updated>1652819174296</updated>
+    </task>
+    <task id="LOCAL-00020" summary="add a badge, change name for the workflow">
+      <created>1652819472258</created>
+      <option name="number" value="00020" />
+      <option name="presentableId" value="LOCAL-00020" />
+      <option name="project" value="LOCAL" />
+      <updated>1652819472258</updated>
+    </task>
+    <option name="localTasksCounter" value="21" />
     <servers />
   </component>
   <component name="Vcs.Log.Tabs.Properties">
@@ -310,7 +339,10 @@
     <MESSAGE value="make test file read-only" />
     <MESSAGE value="use the @NullSource and @EmptySource annotations for tests" />
     <MESSAGE value="add proper test names" />
-    <option name="LAST_COMMIT_MESSAGE" value="add proper test names" />
+    <MESSAGE value="change maven target version to 11" />
+    <MESSAGE value="add maven plugins to run junit5 test with maven" />
+    <MESSAGE value="add a badge, change name for the workflow" />
+    <option name="LAST_COMMIT_MESSAGE" value="add a badge, change name for the workflow" />
     <option name="OPTIMIZE_IMPORTS_BEFORE_PROJECT_COMMIT" value="true" />
     <option name="REFORMAT_BEFORE_PROJECT_COMMIT" value="true" />
     <option name="REARRANGE_BEFORE_PROJECT_COMMIT" value="true" />
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..742effe
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2022 Divyansh Bhardwaj
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
index 5779e48..454aed7 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,4 @@
+[![Test Case Report](https://github.com/dbc2201/JavaCodingProblem1/actions/workflows/maven.yml/badge.svg?event=push)](https://github.com/dbc2201/JavaCodingProblem1/actions/workflows/maven.yml) 
 # Java Coding Problems
 
 ## Chapter 1: Strings, Numbers, and Math
@@ -37,4 +38,4 @@ Write a program that counts duplicate characters from a given `String`.
 **Suggested Reading:**
 
 1. [HashMap (Java SE 18 & JDK 18)](https://docs.oracle.com/en/java/javase/18/docs/api/java.base/java/util/HashMap.html)
-2. [Managing the Content of a Map (dev.java)](https://dev.java/learn/managing-the-content-of-a-map/)
\ No newline at end of file
+2. [Managing the Content of a Map (dev.java)](https://dev.java/learn/managing-the-content-of-a-map/)
diff --git a/pom.xml b/pom.xml
index 1149d30..629d57c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -17,8 +17,31 @@
     </dependencies>
 
     <properties>
-        <maven.compiler.source>18</maven.compiler.source>
-        <maven.compiler.target>18</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
     </properties>
 
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>3.9.0</version>
+                    <configuration>
+                        <source>11</source>
+                        <target>11</target>
+                    </configuration>
+                </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-surefire-plugin</artifactId>
+                    <version>2.22.2</version>
+                </plugin>
+
+            </plugins>
+        </pluginManagement>
+    </build>
+
 </project>
\ No newline at end of file
diff --git a/src/main/java/io/github/dbc/DuplicateCharactersCounter.java b/src/main/java/io/github/dbc/DuplicateCharactersCounter.java
index 9020649..49cee5a 100644
--- a/src/main/java/io/github/dbc/DuplicateCharactersCounter.java
+++ b/src/main/java/io/github/dbc/DuplicateCharactersCounter.java
@@ -8,6 +8,7 @@ public class DuplicateCharactersCounter {
      *
      * @param string String to count duplicate characters.
      * @return Map with characters and their count.
+     * @throws IllegalArgumentException if the input is null or empty.
      */
     public Map<Character, Integer> countDuplicateCharacters(String string) {
         return Map.of();
diff --git a/src/test/java/io/github/dbc/DuplicateCharactersCounterTest.java b/src/test/java/io/github/dbc/DuplicateCharactersCounterTest.java
index 1489a67..537d1df 100644
--- a/src/test/java/io/github/dbc/DuplicateCharactersCounterTest.java
+++ b/src/test/java/io/github/dbc/DuplicateCharactersCounterTest.java
@@ -26,8 +26,7 @@ void shouldReturnMapOfCorrectSize(String input) {
         // Act
         var characterIntegerMap = counter.countDuplicateCharacters(input);
         // Assert
-        assertEquals(input.length(), characterIntegerMap.size(),
-                "the map should have the same size as the input string");
+        assertEquals(input.length(), characterIntegerMap.size(), "the map should have the same size as the input string");
     }
 
     @Test