It might be best just to put a comment saying so if needed. It doesn't really matter if it's there or not. It actually might be clearer to have it.
[Java Reference on Enums](https://docs.oracle.com/javase/specs/jls/se7/html/jls-8.html#jls-8.9) Well spotted @lprone. I will gladly accept a pull request that removes the unnecessary `static`.
static enum
https://github.com/iluwatar/java-design-patterns/blob/55c75799831716b6248ceefa1315881e7f90806b/facade/src/main/java/com/iluwatar/facade/DwarvenMineWorker.java#L89

Enums don't need to be defined as a static. Can change it to :
`
enum Action {
`
facade/src/main/java/com/iluwatar/facade/DwarvenMineWorker.java
facade/src/main/java/com/iluwatar/facade/DwarvenMineWorker.java
diff --git a/facade/src/main/java/com/iluwatar/facade/DwarvenMineWorker.java b/facade/src/main/java/com/iluwatar/facade/DwarvenMineWorker.java
index bb80ae87409d..b313dd9890d9 100644
--- a/facade/src/main/java/com/iluwatar/facade/DwarvenMineWorker.java
+++ b/facade/src/main/java/com/iluwatar/facade/DwarvenMineWorker.java
@@ -86,7 +86,7 @@ public void action(Action... actions) {
 
   public abstract String name();
 
-  static enum Action {
+  enum Action {
     GO_TO_SLEEP, WAKE_UP, GO_HOME, GO_TO_MINE, WORK
   }
 }
