Initial data commit

Task/Extend-your-language/Java/extend-your-language-4.java

@@ -0,0 +1,14 @@
+// prints "both true"
+if2(true, true)
+    .then(() -> print("both true"))
+    .elseIfFirst(() -> print("first true"))
+    .elseIfSecond(() -> print("second true"))
+    .elseNone(() -> print("none true"));
+
+// if we only care about both true and none true...
+// prints "none true"
+if2(false, false)
+    .then(() -> print("both true"))
+    .elseNone(() -> { // a lambda can have a block body
+        print("none true");
+    });