diff --git a/src/CommonElementsFinder.java b/src/CommonElementsFinder.java
index fb88a4b..12256df 100644
--- a/src/CommonElementsFinder.java
+++ b/src/CommonElementsFinder.java
@@ -1,3 +1,4 @@
+import java.util.HashSet;
 import java.util.Set;
 
 /**
@@ -14,8 +15,21 @@ public class CommonElementsFinder {
      * @return a Set<Integer> containing the integers that are present in both arrays
      */
     public static Set<Integer> findCommonElements(int[] array1, int[] array2) {
-        // TODO
-        return null;
+        
+        Set<Integer> arr1Elements = new HashSet<>();
+
+        for(int i = 0; i < array1.length; i++) {
+            arr1Elements.add(array1[i]);
+        }
+
+       Set<Integer> commonElements = new HashSet<>();
+    
+       for(int num : array2) {
+            if(arr1Elements.contains(num)) {
+                commonElements.add(num);
+            }
+       }
+        return commonElements;
     }
 
 
diff --git a/src/DuplicateRemover.java b/src/DuplicateRemover.java
index 8d70003..b27c239 100644
--- a/src/DuplicateRemover.java
+++ b/src/DuplicateRemover.java
@@ -1,4 +1,7 @@
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
+import java.util.TreeSet;
 
 /**
  * The DuplicateRemover class provides a method to remove duplicate words
@@ -15,7 +18,15 @@ public class DuplicateRemover {
      */
     public static List<String> sortAndRemoveDuplicates(String[] words) {
         // TODO
-        return null;
+        Set<String> unique = new TreeSet<>();
+        for(String word : words) {
+            unique.add(word);
+        }
+        List<String> wordList = new ArrayList<>();
+        for(String word : unique) {
+            wordList.add(word);
+        }
+        return wordList;
     }
 
     public static void main(String[] args) {
diff --git a/src/JunitTesting.java b/src/JunitTesting.java
new file mode 100644
index 0000000..be751d0
--- /dev/null
+++ b/src/JunitTesting.java
@@ -0,0 +1,86 @@
+import static org.junit.Assert.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.junit.Test;
+
+public class JunitTesting {
+    @org.junit.jupiter.api.Test
+    void testForCommonElms() {
+        Set<Integer> expected = new HashSet<>(Arrays.asList(4,5,6));
+        assertEquals(expected, CommonElementsFinder.findCommonElements(new int[]{4,5,6}, new int[]{4,5,6}));
+    }
+
+    @org.junit.jupiter.api.Test
+    void testForCommonElms_OneElms() {
+        Set<Integer> expected = new HashSet<>(Arrays.asList(3));
+        assertEquals(expected, CommonElementsFinder.findCommonElements(new int[]{1,2,3}, new int[]{3,4,5}));
+    }
+
+    @org.junit.jupiter.api.Test
+    void testForCommonElms_TwoElms() {
+        Set<Integer> expected = new HashSet<>(Arrays.asList(2,3));
+        assertEquals(expected, CommonElementsFinder.findCommonElements(new int[]{1,2,3}, new int[]{2,3,4,5}));
+    }
+
+    @org.junit.jupiter.api.Test
+    void testForCommonElms_NoCommon() {
+        Set<Integer> expected = new HashSet<>(Arrays.asList());
+        assertEquals(expected, CommonElementsFinder.findCommonElements(new int[]{1,2,3}, new int[]{4,5,6}));
+    }
+
+    @org.junit.jupiter.api.Test
+    void testForUniqueChar() {
+        assertTrue(UniqueCharacterChecker.hasUniqueCharacters("bye"));
+    }
+
+    @org.junit.jupiter.api.Test 
+    void testForNonUniqeChar() {
+        assertFalse(UniqueCharacterChecker.hasUniqueCharacters("Hello"));
+    }
+
+    @org.junit.jupiter.api.Test
+    void testForUniqueChar_null() {
+        assertTrue(UniqueCharacterChecker.hasUniqueCharacters(""));
+    }
+
+    @org.junit.jupiter.api.Test 
+    void testForDuplicateRemover() {
+        List<String> expected = Arrays.asList("bye", "hello");
+        assertEquals(expected, DuplicateRemover.sortAndRemoveDuplicates(new String[]{"bye", "hello", "bye"}));
+    }
+
+    @org.junit.jupiter.api.Test 
+    void testForDuplicateRemover_Null() {
+        List<String> expected = Arrays.asList();
+        assertEquals(expected, DuplicateRemover.sortAndRemoveDuplicates(new String[]{}));
+    }
+
+    @org.junit.jupiter.api.Test 
+    void testForDuplicateRemover_allDup() {
+        List<String> expected = Arrays.asList("bye");
+        assertEquals(expected, DuplicateRemover.sortAndRemoveDuplicates(new String[]{"bye", "bye", "bye", "bye"}));
+    }
+    @org.junit.jupiter.api.Test 
+    void testForDuplicateRemover_case() {
+        List<String> expected = Arrays.asList("Bye", "hello");
+        assertEquals(expected, DuplicateRemover.sortAndRemoveDuplicates(new String[]{"Bye", "hello"}));
+    }
+
+    @org.junit.jupiter.api.Test 
+    void testForDuplicateRemover_caseAllSame() {
+        List<String> expected = Arrays.asList("Hello", "hello");
+        assertEquals(expected, DuplicateRemover.sortAndRemoveDuplicates(new String[]{"Hello", "Hello", "Hello", "hello"}));
+    }
+}
+
+
+
+
+
+
diff --git a/src/UniqueCharacterChecker.java b/src/UniqueCharacterChecker.java
index 554ffc4..8bab9ba 100644
--- a/src/UniqueCharacterChecker.java
+++ b/src/UniqueCharacterChecker.java
@@ -1,3 +1,7 @@
+import java.util.HashSet;
+import java.util.Set;
+import java.util.TreeSet;
+
 /**
  * The UniqueCharacterChecker class provides a method to check if all characters
  * in a given word are unique.
@@ -14,7 +18,16 @@ public static boolean hasUniqueCharacters(String word) {
         // TODO: implement this!
         // Requirement: This must run in O(n) time, where n is the number of characters in the word
         // Hint: Stuck? Consider looking up "charAt" and seeing how it can help you
-        return false;
+        Set<Character> seenChar = new HashSet<>();
+        for(int i = 0; i < word.length(); i++) {
+            char c = word.charAt(i);
+            if(seenChar.contains(c)) {
+                return false;
+            }
+            seenChar.add(c);
+        }
+       
+        return true;
     }
 
     public static void main(String[] args) {