Initial data commit

Task/Delegates/Java/delegates-3.java

@@ -0,0 +1,19 @@
+package delegate;
+
+import java.util.Optional;
+
+public interface Delegator {
+  public Thingable delegate();
+  public Delegator delegate(Thingable thingable);
+
+  public static Delegator new_() {
+    return $Delegator.new_();
+  }
+
+  public default String operation() {
+    return Optional.ofNullable(delegate())
+      .map(Thingable::thing)
+      .orElse("default implementation")
+    ;
+  }
+}