diff --git a/chapter-12/dedup.java b/chapter-12/dedup.java
new file mode 100644
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--- /dev/null
+++ b/chapter-12/dedup.java
@@ -0,0 +1,15 @@
+/* Write a recursive method called dedup that takes a string as a parameter and that returns a new string
+obtained by replacing every sequence of repeated adjacent letters with just one of that letter. For example,
+the string "bookkkkkeeper" has three repeated adjacent letters ("oo", "kkkkk", and "ee"), so the call of dedup("bookkkkkeeper")
+should return "bokeper". Do not call the string replace or split methods in your solution.*/
+
+public static String dedup(String s) {
+        if (s.length() == 1) {
+            return s;
+        }
+        if (s.charAt(0) != s.charAt(1)) {
+            String newS = Character.toString(s.charAt(0));
+            return newS + dedup(s.substring(1));
+        }
+        return dedup(s.substring(1));
+    }