Add first cut at Java interop

src/koans/java_interop.clj

@@ -0,0 +1,16 @@
+(meditations
+  "You may have done more with Java than you know"
+  (= __ (class "warfare")) ; hint: try typing (javadoc "warfare") in the REPL
+
+  "The dot signifies easy and direct Java interoperation"
+  (= __ (.toUpperCase "select * from"))
+
+  "But instance method calls are very different from normal functions"
+  (= ["SELECT" "FROM" "WHERE"] (map ___ ["select" "from" "where"]))
+
+  "Constructing might be harder than breaking"
+  (= 10 (let [latch (java.util.concurrent.CountDownLatch. __)]
+          (.getCount latch)))
+
+  "Static methods are slashing prices!"
+  (== __ (Math/pow 2 10)))

src/path_to_answer_sheet.clj

@@ -192,7 +192,18 @@
                       nil
                       [true false]
                       (str "Congratulations on your Best Picture Oscar, "
-                           "Evil Alien Conquerors!")]}})
+                           "Evil Alien Conquerors!")]}
+
+   "java_interop" {"__" ['java.lang.String
+                         "SELECT * FROM"
+                         10
+                         1024
+                         ]
+                   "___" ['#(.toUpperCase %)
+                          ]
+                   }
+
+   })
 
 (defn replace-with [s k replacements]
   (let [unreplaced-texts (split s (re-pattern (str "\\b" k "\\b")))]

src/runner/koans.clj

@@ -19,7 +19,8 @@
       "refs"
       "atoms"
       "macros"
-      "datatypes"])
+      "datatypes"
+      "java_interop"])
 
 (defn ordered-koan-paths  []
   (map (fn [koan-name]