Solution #1 - Java6 compatible introducing an enum for response type

.gitignore

@@ -3,4 +3,5 @@ java/build
 java/.classpath
 java/.project
 java/.settings
-*.class
+*.class
+java/.gradle

java/build.gradle

@@ -1,6 +1,7 @@
 apply plugin: 'java'
+apply plugin: 'eclipse'
 
-sourceCompatibility = 1.7
+sourceCompatibility = 1.6
 group = 'it.tug'
 version = '0.1'
 

java/src/main/java/it/tug/Main/Formatter.java

@@ -10,10 +10,10 @@ public Formatter(Service service) {
 
     public String doTheJob(String theInput) {
         String response = service.askForPermission();
-        switch (response) {
-            case "FAIL":
+        switch (ResponseType.getType(response)) {
+            case FAIL:
                 return "error";
-            case "OK":
+            case OK:
                 return String.format("%s%s", theInput, theInput);
             default:
                 return null;

java/src/main/java/it/tug/Main/ResponseType.java

@@ -0,0 +1,13 @@
+package it.tug.Main;
+
+public enum ResponseType {
+	FAIL, OK, OTHER;
+
+	static ResponseType getType(String type) {
+		try {
+			return valueOf(type);
+		} catch (IllegalArgumentException e) {
+			return OTHER;
+		}
+	}
+}