Add all the A tasks

Task/Anonymous-recursion/Java/anonymous-recursion-2.java

@@ -0,0 +1,24 @@
+import java.util.function.Function;
+
+@FunctionalInterface
+interface SelfApplicable<OUTPUT> {
+  OUTPUT apply(SelfApplicable<OUTPUT> input);
+}
+
+class Utils {
+  public static <INPUT, OUTPUT> SelfApplicable<Function<Function<Function<INPUT, OUTPUT>, Function<INPUT, OUTPUT>>, Function<INPUT, OUTPUT>>> y(Class<INPUT> input, Class<OUTPUT> output) {
+    return y -> f -> x -> f.apply(y.apply(y).apply(f)).apply(x);
+  }
+
+  public static <INPUT, OUTPUT> Function<Function<Function<INPUT, OUTPUT>, Function<INPUT, OUTPUT>>, Function<INPUT, OUTPUT>> fix(Class<INPUT> input, Class<OUTPUT> output) {
+    return y(input, output).apply(y(input, output));
+  }
+
+  public static long fib(int m) {
+    if (m < 0)
+      throw new IllegalArgumentException("n can not be a negative number");
+    return fix(Integer.class, Long.class).apply(
+      f -> n -> (n < 2) ? n : (f.apply(n - 1) + f.apply(n - 2))
+    ).apply(m);
+  }
+}