diff --git a/src/main/java/io/zipcoder/Problem1.java b/src/main/java/io/zipcoder/Problem1.java
index 6cd6024..cd96273 100644
--- a/src/main/java/io/zipcoder/Problem1.java
+++ b/src/main/java/io/zipcoder/Problem1.java
@@ -1,4 +1,31 @@
 package io.zipcoder;
 
+
+import java.util.Map;
+
+// Given the following map { ‘f’ : ‘7’, ‘s’:’$’, ‘1’:’!’, ‘a’.:’@’},
+// your method should replace any character represented by a key in the map, with its corresponding value.
+//
+// Input = “The Farmer went to the store to get 1 dollar’s worth of fertilizer”
+// Output = “The 7@rmer went to the $tore to get ! doll@r’$ worth of 7ertilizer”
 public class Problem1 {
+
+
+
+    public static String replaceCharsInString(String input,Map<Character,Character> map) {
+        StringBuilder builder = new StringBuilder();
+
+        for(int i = 0; i < input.length(); i++ ) {
+            Character currentChar = input.charAt(i);
+
+            if (map.containsKey(currentChar)) {
+                currentChar = map.get(currentChar);
+                //get returns the value of the key
+            }
+            builder.append(currentChar);
+        }
+        return builder.toString();
+    }
+
+
 }
diff --git a/src/test/java/io/zipcoder/Problem1Test.java b/src/test/java/io/zipcoder/Problem1Test.java
index de82e99..0c41540 100644
--- a/src/test/java/io/zipcoder/Problem1Test.java
+++ b/src/test/java/io/zipcoder/Problem1Test.java
@@ -1,4 +1,36 @@
 package io.zipcoder;
 
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.HashMap;
+
 public class Problem1Test {
+
+    Problem1 problem1;
+    HashMap<Character,Character> map;
+    String input;
+
+    @Before
+    public void setUp() {
+        map = new HashMap<Character, Character>();
+        map.put('f', '7');
+        map.put('s', '$');
+        map.put('1', '!');
+        map.put('a', '@');
+        problem1 = new Problem1();
+        input = "The farmer went to the store to get 1 dollar’s worth of fertilizer";
+
+    }
+
+    @Test
+    public void Test(){
+
+
+        String expected = "The 7@rmer went to the $tore to get ! doll@r’$ worth o7 7ertilizer";
+        String actual = Problem1.replaceCharsInString(input,map);
+
+        Assert.assertEquals(expected,actual);
+    }
 }