diff --git a/src/main/java/com/dtcc/exams/part1/BasicUtilities.java b/src/main/java/com/dtcc/exams/part1/BasicUtilities.java
index 640df37..b858555 100644
--- a/src/main/java/com/dtcc/exams/part1/BasicUtilities.java
+++ b/src/main/java/com/dtcc/exams/part1/BasicUtilities.java
@@ -1,21 +1,36 @@
 package com.dtcc.exams.part1;
 
 public class BasicUtilities {
+    private int input;
 
     public Boolean isGreaterThan5(Integer value) {
-        return null;
+        if(value >= 5){
+            return true;
+        }else
+            return false;
     }
 
     public Boolean isLessThan7(Integer value) {
-        return null;
+        if(value <= 7){
+            return true;
+        }else
+            return false;
     }
 
     public Boolean isBetween5And7(Integer valueToEvaluate) {
-        return null;
+        if(valueToEvaluate >= 5 && valueToEvaluate <=7){
+            return true;
+        }else
+            return false;
     }
 
     public Boolean startsWith(String string, Character character) {
-        return null;
+       char c = string.toLowerCase().charAt(0);
+       char lchar = Character.toLowerCase(character);
+        if(lchar==c){
+            return true;
+        }else
+            return false;
     }
 
 }
\ No newline at end of file
diff --git a/src/main/java/com/dtcc/exams/part1/DelTechConcatenator.java b/src/main/java/com/dtcc/exams/part1/DelTechConcatenator.java
index 61abcdd..503c3df 100644
--- a/src/main/java/com/dtcc/exams/part1/DelTechConcatenator.java
+++ b/src/main/java/com/dtcc/exams/part1/DelTechConcatenator.java
@@ -1,20 +1,30 @@
 package com.dtcc.exams.part1;
 
 public class DelTechConcatenator {
-
+private double input;
     public DelTechConcatenator(Integer input) {
+   this.input =input;
     }
 
     public Boolean isDel() {
-        return null;
+        if(input % 3 == 0){
+            return true;
+        }else
+            return false;
     }
 
     public Boolean isTech() {
-        return null;
+        if(input % 5 == 0){
+            return true;
+        }else
+        return false;
     }
 
     public Boolean isDelTech() {
-        return null;
+        if(input % 3 == 0 && input % 5 == 0){
+            return true;
+        }else
+            return false;
     }
 
 }
diff --git a/src/main/java/com/dtcc/exams/part1/IntegerArrayUtilities.java b/src/main/java/com/dtcc/exams/part1/IntegerArrayUtilities.java
index a7e9aaa..5e8823d 100644
--- a/src/main/java/com/dtcc/exams/part1/IntegerArrayUtilities.java
+++ b/src/main/java/com/dtcc/exams/part1/IntegerArrayUtilities.java
@@ -1,21 +1,35 @@
 package com.dtcc.exams.part1;
 
+import java.util.ArrayList;
+
 public class IntegerArrayUtilities {
 
     public Boolean hasEvenLength(Integer[] array) {
-        return null;
+        int arrayLength = array.length;
+        if(arrayLength % 2 == 0){
+            return true;
+        }
+        else return false;
     }
 
     public Integer[] range(int start, int stop) {
-        return null;
+       ArrayList<Integer> arr = new ArrayList<Integer>();
+         for(int i = start; i < stop + 1; i++){
+           arr.add(i);
+        }
+         return arr.toArray(new Integer[0]);
     }
 
     public Integer getSumOfFirstTwo(Integer[] array) {
-        return null;
+        int sum = 0;
+            sum = array[0] + array[1];
+        return sum;
     }
 
     public Integer getProductOfFirstTwo(Integer[] array) {
-        return null;
+
+           return array[array.length-1] * array[array.length-2];
+
     }
 
 }
diff --git a/src/main/java/com/dtcc/exams/part2/ArrayUtility.java b/src/main/java/com/dtcc/exams/part2/ArrayUtility.java
index 41885cb..fc25500 100644
--- a/src/main/java/com/dtcc/exams/part2/ArrayUtility.java
+++ b/src/main/java/com/dtcc/exams/part2/ArrayUtility.java
@@ -1,21 +1,82 @@
 package com.dtcc.exams.part2;
 
+import java.lang.reflect.Array;
+import java.util.ArrayList;
+import java.lang.Integer;
+import java.util.Arrays;
+import java.util.List;
+
 public class ArrayUtility {
 
     public Integer[] merge(Integer[] array1, Integer[] array2) {
-        return null;
-    }
+        ArrayList<Integer> mergeList = new ArrayList<>();
+        mergeList.addAll(Arrays.asList(array1));
+        mergeList.addAll(Arrays.asList(array2));
+        Integer[] item = mergeList.toArray(new Integer[mergeList.size()]);
+        return item;
+    }    
+
+    public Integer[] rotate(Integer[] array, int index) {
+        Integer[] result = new Integer[array.length];
+
+
+        int j=0;
+        for(int i=index; i<array.length; i++){
+            result[j] = array[i];
+            j++;
+        }
+        for(int i=0; i < index; i++){
+            result[j] = array[i];
+            j++;
+        }
+
+//        System.arraycopy( result, 0, array, 0, array.length );
+        return result;
 
-    public Integer[] rotate(Integer[] array, Integer index) {
-        return null;
     }
 
     public Integer countOccurrence(Integer[] array1, Integer[] array2, Integer valueToEvaluate) {
-        return null;
-    }
+        int count1 = 0;
+        int count2 = 0;
+        for(int i = 0; i < array1.length; i++ ){
+            if(array1[i] == valueToEvaluate){
+                count1++;
+            }}
+            for(int j = 0; j < array2.length; j++){
+                if(array2[j] == valueToEvaluate){
+                    count2++;
+                }  }
+            return count1 + count2;
+        }
+
+
+
 
     public Integer mostCommon(Integer[] array) {
-        return null;
-    }
+        Arrays.sort(array);
+        int curr_count =0;
+        int max_count = 1;
+        Integer res = array[0];
+        for (int i = 1; i < array.length; i++) {
+            if (array[i] == array[i - 1])
+                curr_count++;
+            else {
+                if (curr_count > max_count) {
+                    max_count = curr_count;
+                    res = array[i - 1];
+                }
+                curr_count = 1;
+            }
+        }
+
+        // If last element is most frequent
+        if (curr_count > max_count)
+        {
+            max_count = curr_count;
+            res = array[array.length - 1];
+        }
+
+        return res;
+
 
-}
+    }}
diff --git a/src/main/java/com/dtcc/exams/part2/ListUtility.java b/src/main/java/com/dtcc/exams/part2/ListUtility.java
index 4c4e910..2c39832 100644
--- a/src/main/java/com/dtcc/exams/part2/ListUtility.java
+++ b/src/main/java/com/dtcc/exams/part2/ListUtility.java
@@ -1,31 +1,59 @@
 package com.dtcc.exams.part2;
 
+import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 public class ListUtility {
 
+    public ArrayList<Integer> list = new ArrayList<>();
+
     public Boolean add(int i) {
-        return null;
+        //if (null==(Integer)i) { return false; }
+        return list.add(i);
+        //return null;
     }
 
     public Integer size() {
-        return null;
+       return list.size();
     }
 
     public List<Integer> getUnique() {
-        return null;
+        ArrayList<Integer> newlist = new ArrayList<>();
+        for (Integer element : list) {
+            if (!newlist.contains(element)) {
+                newlist.add(element);
+            }
+        }
+        return newlist;
     }
 
     public String join() {
-        return null;
+        String joined="";
+        for(int i=0;i< list.size();i++){
+            joined += list.get(i);
+           if(i<=list.size()-2) {joined += ", "; }
+        }
+        return joined;
     }
 
+
     public Integer mostCommon() {
         return null;
     }
 
     public Boolean contains(Integer valueToAdd) {
-        return null;
+
+        if((Integer)valueToAdd != null) {
+            if (list.contains(valueToAdd)) {
+                return true;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
     }
 
 }
+
diff --git a/src/main/java/com/dtcc/exams/part2/Router.java b/src/main/java/com/dtcc/exams/part2/Router.java
index 3c699b6..8eb8a1b 100644
--- a/src/main/java/com/dtcc/exams/part2/Router.java
+++ b/src/main/java/com/dtcc/exams/part2/Router.java
@@ -1,22 +1,46 @@
 package com.dtcc.exams.part2;
 
+import java.util.HashMap;
+import java.util.Map;
+
 public class Router {
+    Map<String,String> hash_map = new HashMap<String,String>();
 
     public void add(String path, String controller) {
+
+        hash_map.put(path, controller);
+
     }
 
     public Integer size() {
-        return null;
+        return this.hash_map.size();
     }
 
     public String getController(String path) {
-        return null;
+        String value=null;
+        for(Map.Entry key:hash_map.entrySet()){        //this is how you traverse through the map.(Set)
+            if(key.getKey().equals(path)){
+                value= (String) key.getValue();
+            }
+        }
+        return value;
     }
 
+
     public void update(String path, String studentController) {
+        for(Map.Entry key:this.hash_map.entrySet()) {
+            if (key.getKey().equals(path)) {
+                key.setValue(studentController);
+            }
+        }
     }
 
     public void remove(String path) {
+        for(Map.Entry key:this.hash_map.entrySet()) {
+            if (key.getKey().equals(path)) {
+                hash_map.remove(path);
+            }
+        }
     }
 
 }
diff --git a/src/main/java/com/dtcc/exams/part3/Bird.java b/src/main/java/com/dtcc/exams/part3/Bird.java
index a24cbd8..6b64410 100644
--- a/src/main/java/com/dtcc/exams/part3/Bird.java
+++ b/src/main/java/com/dtcc/exams/part3/Bird.java
@@ -1,8 +1,18 @@
 package com.dtcc.exams.part3;
 
-public class Bird {
+public class Bird implements Animal{
 
     public String move() {
+        return "fly";
+    }
+
+    @Override
+    public int getSpeed() {
+        return 0;
+    }
+
+    @Override
+    public String color() {
         return null;
     }
 
diff --git a/src/main/java/com/dtcc/exams/part3/Horse.java b/src/main/java/com/dtcc/exams/part3/Horse.java
index c02e088..121a17b 100644
--- a/src/main/java/com/dtcc/exams/part3/Horse.java
+++ b/src/main/java/com/dtcc/exams/part3/Horse.java
@@ -1,4 +1,19 @@
 package com.dtcc.exams.part3;
 
-public class Horse {
+public class Horse implements Animal{
+
+    @Override
+    public String move() {
+        return "gallop";
+    }
+
+    @Override
+    public int getSpeed() {
+        return 40;
+    }
+
+    @Override
+    public String color() {
+        return "black";
+    }
 }
diff --git a/src/main/java/com/dtcc/exams/part3/PeregrineFalcon.java b/src/main/java/com/dtcc/exams/part3/PeregrineFalcon.java
index b5c53b3..09d0a57 100644
--- a/src/main/java/com/dtcc/exams/part3/PeregrineFalcon.java
+++ b/src/main/java/com/dtcc/exams/part3/PeregrineFalcon.java
@@ -1,4 +1,13 @@
 package com.dtcc.exams.part3;
 
-public class PeregrineFalcon {
+public class PeregrineFalcon extends Bird{
+    @Override
+    public int getSpeed() {
+        return 13;
+    }
+
+    @Override
+    public String color() {
+        return "brown";
+    }
 }
diff --git a/src/main/java/com/dtcc/exams/part3/RedRobin.java b/src/main/java/com/dtcc/exams/part3/RedRobin.java
index 49fd626..d93d75e 100644
--- a/src/main/java/com/dtcc/exams/part3/RedRobin.java
+++ b/src/main/java/com/dtcc/exams/part3/RedRobin.java
@@ -1,4 +1,24 @@
 package com.dtcc.exams.part3;
 
-public class RedRobin {
+public class RedRobin extends Bird{
+    String migrationMonth;
+    @Override
+    public int getSpeed() {
+        return 10;
+    }
+
+    @Override
+    public String color() {
+        return "red";
+    }
+
+    @Override
+    public String getMigrationMonth() {
+        return migrationMonth;
+    }
+
+    @Override
+    public void setMigrationMonth(String migrationMonth) {
+        this.migrationMonth = migrationMonth;
+    }
 }
diff --git a/src/main/java/com/dtcc/exams/part3/SpeedComparator.java b/src/main/java/com/dtcc/exams/part3/SpeedComparator.java
index 2aa8c7f..55932bd 100644
--- a/src/main/java/com/dtcc/exams/part3/SpeedComparator.java
+++ b/src/main/java/com/dtcc/exams/part3/SpeedComparator.java
@@ -1,4 +1,19 @@
 package com.dtcc.exams.part3;
 
-public class SpeedComparator {
-}
+import java.util.Comparator;
+
+public class SpeedComparator implements Comparator<Animal> {
+
+    @Override
+    public int compare(Animal animal1, Animal animal2) {
+        if(animal1.getSpeed() == animal2.getSpeed()){
+            return 0;
+        }
+        else if(animal1.getSpeed() > animal2.getSpeed()){
+            return -1;
+        }
+        else if(animal1.getSpeed() < animal2.getSpeed()){
+            return 1;
+        }
+    return 1;
+}}
diff --git a/src/test/java/com/dtcc/exams/TestUtils.java b/src/test/java/com/dtcc/exams/TestUtils.java
index acd6404..86ccb06 100644
--- a/src/test/java/com/dtcc/exams/TestUtils.java
+++ b/src/test/java/com/dtcc/exams/TestUtils.java
@@ -2,6 +2,7 @@
 
 import org.junit.Assert;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 
 public class TestUtils {
diff --git a/src/test/java/com/dtcc/exams/part2/arrayutility/MergeTest.java b/src/test/java/com/dtcc/exams/part2/arrayutility/MergeTest.java
index 4baf983..da5e4bb 100644
--- a/src/test/java/com/dtcc/exams/part2/arrayutility/MergeTest.java
+++ b/src/test/java/com/dtcc/exams/part2/arrayutility/MergeTest.java
@@ -5,6 +5,8 @@
 import org.junit.Before;
 import org.junit.Test;
 
+import java.util.ArrayList;
+
 public class MergeTest {
 
     private ArrayUtility utility;
diff --git a/src/test/java/com/dtcc/exams/part2/listutility/AddTest.java b/src/test/java/com/dtcc/exams/part2/listutility/AddTest.java
index 4644f23..148f188 100644
--- a/src/test/java/com/dtcc/exams/part2/listutility/AddTest.java
+++ b/src/test/java/com/dtcc/exams/part2/listutility/AddTest.java
@@ -7,22 +7,22 @@
 public class AddTest {
     @Test
     public void test1() {
-        test(1);
+        this.test(1);
     }
 
     @Test
     public void test2() {
-        test(2);
+        this.test(2);
     }
 
     @Test
     public void test3() {
-        test(3);
+        this.test(3);
     }
 
     @Test
     public void test4() {
-        test(null);
+        this.test(null);
     }