Create mapAB3.java

Modify and return the given map as follows: if exactly one of the keys "a" or "b" has a value in the map (but not both), set the other to have that same value in the map.

mapAB3({"a": "aaa", "c": "cake"}) → {"a": "aaa", "b": "aaa", "c": "cake"}
mapAB3({"b": "bbb", "c": "cake"}) → {"a": "bbb", "b": "bbb", "c": "cake"}
mapAB3({"a": "aaa", "b": "bbb", "c": "cake"}) → {"a": "aaa", "b": "bbb", "c": "cake"}

Map-1/mapAB3.java

@@ -0,0 +1,16 @@
+/*
+Modify and return the given map as follows: if exactly one of the keys "a" or "b" has a value in the map (but not both), set the other to have that same value in the map.
+
+mapAB3({"a": "aaa", "c": "cake"}) → {"a": "aaa", "b": "aaa", "c": "cake"}
+mapAB3({"b": "bbb", "c": "cake"}) → {"a": "bbb", "b": "bbb", "c": "cake"}
+mapAB3({"a": "aaa", "b": "bbb", "c": "cake"}) → {"a": "aaa", "b": "bbb", "c": "cake"}
+*/
+public Map<String, String> mapAB3(Map<String, String> map) {
+  if(map.containsKey("a") && !map.containsKey("b")) {
+    map.put("b" , map.get("a"));
+  }
+  if(map.containsKey("b") && !map.containsKey("a")) {
+    map.put("a" , map.get("b"));
+  }
+  return map;
+}