improved java docs

src/test/java/ch/zhaw/pm2/racetrack/GameTest.java

@@ -200,13 +200,13 @@ class GameTest {
     }
 
     /**
-     * This Class is used to communicate with the UserInterface. It overrides crucial methods and returns an instruction based on the instructions data field.
+     * This Class is used to communicate with the UserInterface. It overrides crucial methods and returns an instruction based on the instructions' data field.
      * To implement the right instructions the user has to be aware of the game sequence.
      */
     private class interFace extends UserInterface {
 
-        private PositionVector.Direction[] directions;
-        private Integer[] instructions;
+        private final PositionVector.Direction[] directions;
+        private final Integer[] instructions;
         private int pointerDir,pointerInstruction;