diff --git a/src/main/java/com/dtcc/projects/PhoneBook.java b/src/main/java/com/dtcc/projects/PhoneBook.java
index 37094f3..8f22380 100644
--- a/src/main/java/com/dtcc/projects/PhoneBook.java
+++ b/src/main/java/com/dtcc/projects/PhoneBook.java
@@ -1,4 +1,71 @@
 package com.dtcc.projects;
 
+import java.util.*;
+
 public class PhoneBook {
+    Map<String, List<String>> phoneBookMap;
+
+    public PhoneBook(){
+        this(new LinkedHashMap<String,List<String>>());
+    }
+
+    public PhoneBook(Map<String,List<String>> map){
+        this.phoneBookMap=map;
+    }
+
+    public void add(String name,String phoneNumber){
+        List<String> phoneNumberList=phoneBookMap.get(name);
+       if(phoneNumberList!=null){
+           phoneNumberList.add(phoneNumber);
+       }
+       else{
+           phoneBookMap.put(name,Collections.singletonList(phoneNumber));
+       }
+    }
+
+    public void addAll(String name, String[] pnumbers){
+        if(!phoneBookMap.containsKey(name)) {
+            phoneBookMap.put(name,Arrays.asList(pnumbers));
+        }
+    }
+
+    public void remove(String name){
+        if(phoneBookMap.containsKey(name))
+            phoneBookMap.remove(name);
+    }
+
+    public boolean hasEntry(String name){
+        return phoneBookMap.containsKey(name);
+    }
+
+    public List<String> lookup(String name){
+      /*  List<String> sendList=new ArrayList<>();
+        for(Map.Entry<String,List<String>> e: phoneBookMap.entrySet()){
+            if(e.getKey().equalsIgnoreCase(name)){
+                sendList= e.getValue();
+            }
+        }*/
+        return phoneBookMap.get(name);
+    }
+
+    public String reverseLookup(String phoneNumber){
+        String strName="";
+        for(Map.Entry<String,List<String>> e: phoneBookMap.entrySet()) {
+            if(e.getValue().contains(phoneNumber)){
+                strName=e.getKey();
+            }
+        }
+        return strName;
+    }
+
+    public List<String> getAllContactNames(){
+        List<String> keyList=new ArrayList<>();
+        if(phoneBookMap!=null){
+            for(String s : phoneBookMap.keySet()){
+                keyList.add(s);
+            }
+        }
+          return keyList;
+    }
+
 }
diff --git a/src/test/java/com/dtcc/projects/PhoneBookTest.java b/src/test/java/com/dtcc/projects/PhoneBookTest.java
index 891889e..67aee23 100644
--- a/src/test/java/com/dtcc/projects/PhoneBookTest.java
+++ b/src/test/java/com/dtcc/projects/PhoneBookTest.java
@@ -1,4 +1,88 @@
 package com.dtcc.projects;
 
+import org.junit.Assert;
+import org.junit.Assert.*;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.*;
+
 public class PhoneBookTest {
+
+    PhoneBook phoneBook;
+    @Before
+    public void setup(){
+        phoneBook=new PhoneBook();
+    }
+
+    @Test
+    public void testAdd(){
+        String name="Charu";
+        String phoneNumber="123-123-1234";
+        phoneBook.add(name,phoneNumber);
+        Assert.assertTrue(phoneBook.phoneBookMap.containsKey(name));
+        Assert.assertEquals(phoneNumber,phoneBook.phoneBookMap.get(name).get(0));
+    }
+
+    @Test
+    public void tesAddAll(){
+        String[] list= {"123-123-123","456-345-8934"};
+        String name="Nitu";
+        phoneBook.addAll(name,list);
+        Assert.assertEquals(2,phoneBook.phoneBookMap.get(name).size());
+        Assert.assertEquals(Arrays.asList(list),phoneBook.phoneBookMap.get(name));
+    }
+
+    @Test
+    public void testRemoveKey(){
+        String name="Sam";
+        String phoneNumber="456-678-0987";
+        phoneBook.add(name,phoneNumber);
+        phoneBook.remove(name);
+        Assert.assertEquals(false,phoneBook.phoneBookMap.containsKey(name));
+    }
+
+    @Test
+    public void testHasEntry(){
+        String[] list={"123-132-127","456-345-8934"};
+        String name="Ramona";
+        phoneBook.addAll(name,list);
+        Assert.assertTrue(phoneBook.hasEntry(name));
+    }
+
+    @Test
+    public void testLookup(){
+        String[] list={"123-132-127","456-345-8934"};
+        String name="Seher";
+        phoneBook.addAll(name,list);
+        List<String> nameList=phoneBook.lookup(name);
+        Assert.assertEquals(Arrays.asList(list),nameList);
+    }
+
+    @Test
+    public void testReverseLookup(){
+        String actual="Rakhi";
+        String phoneNumber="123-123-4564";
+        phoneBook.add(actual,phoneNumber);
+        String expected=phoneBook.reverseLookup(phoneNumber);
+        Assert.assertEquals(actual,expected);
+    }
+
+    @Test
+    public void testGetAllContactNames(){
+        List<String> expectedList=new ArrayList<>();
+        List<String> actual=new ArrayList<>();
+        String name1="Seema";
+        String phoneNumber="123-123-4564";
+        String name2="Shreya";
+        String[] strList={"123-132-127","456-345-8934"};
+        actual.add(name1);
+        actual.add(name2);
+        phoneBook.add(name1,phoneNumber);
+        phoneBook.addAll(name2,strList);
+        expectedList=phoneBook.getAllContactNames();
+        Assert.assertEquals(actual,expectedList);
+
+    }
+
 }