Exercise extension complete

Author: hannaklh

src/main/java/com/booleanuk/extension/Extension.java

@@ -27,11 +27,7 @@ public StringBuilder one() {
         StringBuilder sb = new StringBuilder();
 
         // 1. Using the sb variable above, add "Hello, world!" to the StringBuilder
-        // WRITE YOUR CODE BETWEEN THIS LINE...
-
-
-
-        // ...AND THIS LINE
+        sb.append("Hello, world!");
 
         return sb;
     }
@@ -41,11 +37,8 @@ public StringBuilder two() {
 
         // 1. Using the sb variable above, add "Hello, world!" to the StringBuilder
         // 2. After adding the message, use an appropriate StringBuilder method to reverse it
-        // WRITE YOUR CODE BETWEEN THIS LINE...
-
-
-
-        // ...AND THIS LINE
+        sb.append("Hello, world!");
+        sb.reverse();
 
         return sb;
     }
@@ -55,11 +48,8 @@ public StringBuilder three() {
 
         // 1. Using the sb variable above, add "Hello, world!" to the StringBuilder
         // 2. After adding the message, remove the comma.
-        // WRITE YOUR CODE BETWEEN THIS LINE...
-
-
-
-        // ...AND THIS LINE
+        sb.append("Hello, world!");
+        sb.deleteCharAt(5);
 
         return sb;
     }
@@ -69,11 +59,8 @@ public StringBuilder four() {
 
         // 1. Using the sb variable above, add "Hello, world!" to the StringBuilder
         // 2. After adding the message, replace the word "world" with the word "Java"
-        // WRITE YOUR CODE BETWEEN THIS LINE...
-
-
-
-        // ...AND THIS LINE
+        sb.append("Hello, world!");
+        sb.replace(7,12, "Java");
 
         return sb;
     }