Update README.md

janbodnar · web-flow · commit 74f32eea05a5 · 2019-09-02T12:50:32.000+02:00
diff --git a/async/README.md b/async/README.md
@@ -1,3 +1,15 @@
-*CompletableFuture* is a tool for asynchronous programming in Java. Asynchronous programming is writing 
+`Future` is a placeholder for a result of an operation that hasn't finished yet. 
+Once the operation finishes, the `Future` will contain that result.
+
+Limitations of futures:
+
+* they cannot be manually completed
+* no further action on a Future's result without blocking
+* multiple Futures cannot be chained or combined
+* there is no exception handling construct
+
+`CompletableFuture` was introduced to fix the limitations of `Future`. 
+
+`CompletableFuture` is a tool for asynchronous programming in Java. Asynchronous programming is writing 
 non-blocking code by running a task on a separate thread than the main application thread
 and notifying the main thread about its progress, completion, or failure.
