public class VacuumRobot
{
    public static final char UP = '^';
    public static final char DOWN = 'v';
    public static final char RIGHT = '<';
    public static final char LEFT = '>';
    public static final char TUMBLING = 'X';

    public VacuumRobot ()
    {

    }
}
@@ -48,21 +48,23 @@
 nal 
-char
+String
  UP = 
-'%5E'
+%22%5E%22
 ;%0A  
@@ -89,20 +89,22 @@
 nal 
-char
+String
  DOWN = 
 'v';
@@ -103,11 +103,11 @@
 N = 
-'v'
+%22v%22
 ;%0A  
@@ -128,20 +128,22 @@
 c final 
-char
+String
  RIGHT =
@@ -147,11 +147,11 @@
 T = 
-'%3C'
+%22%3C%22
 ;%0A  
@@ -176,20 +176,22 @@
 nal 
-char
+String
  LEFT = 
 '%3E';
@@ -190,95 +190,1155 @@
 T = 
-'%3E';%0A    public static final char TUMBLING = 'X';%0A%0A    public VacuumRobot ()%0A    %7B%0A%0A    %7D
+%22%3E%22;%0A    public static final String TUMBLING = %22X%22;%0A%0A    // ASCII codes.%0A%0A    public static final String UP_CODE = %2294%22;%0A    public static final String DOWN_CODE = %22118%22;%0A    public static final String RIGHT_CODE = %2260%22;%0A    public static final String LEFT_CODE = %2262%22;%0A    public static final String TUMBLING_CODE = %2288%22;%0A%0A    public VacuumRobot (boolean debug)%0A    %7B%0A        _debug = debug;%0A    %7D%0A%0A    public static final String print (String code)%0A    %7B%0A        switch (code)%0A        %7B%0A            case UP_CODE:%0A                return UP;%0A            case DOWN_CODE:%0A                return DOWN;%0A            case RIGHT_CODE:%0A                return RIGHT;%0A            case LEFT_CODE:%0A                return LEFT;%0A            default:%0A                return TUMBLING;%0A        %7D%0A    %7D%0A%0A    public static final boolean isRobotCode (String code)%0A    %7B%0A        switch (code)%0A        %7B%0A            case UP_CODE:%0A            case DOWN_CODE:%0A            case RIGHT_CODE:%0A            case LEFT_CODE:%0A            case TUMBLING_CODE:%0A                return true;%0A            default:%0A                return false;%0A        %7D%0A    %7D%0A%0A    private boolean _debug;
 %0A%7D

Update VacuumRobot.java