!per #17518 harmonize and document failure handling in persistence

+ added tests for all failure scenarios (callbacks)

akka-docs/rst/java/code/docs/persistence/LambdaPersistenceDocTest.java

@@ -258,6 +258,16 @@ public class LambdaPersistenceDocTest {
   static Object o5 = new Object() {
 
     class MyPersistentActor extends AbstractPersistentActor {
+
+      //#snapshot-criteria
+      @Override
+      public Recovery recovery() {
+        return Recovery.create(
+          SnapshotSelectionCriteria
+            .create(457L, System.currentTimeMillis()));
+      }
+      //#snapshot-criteria
+
       //#snapshot-offer
       private Object state;
 
@@ -291,14 +301,6 @@ public class LambdaPersistenceDocTest {
           match(Object.class, o -> {/* ... */}).build()
         );
       }
-
-      private void recover() {
-        //#snapshot-criteria
-        persistentActor.tell(Recovery.create(
-          SnapshotSelectionCriteria
-            .create(457L, System.currentTimeMillis())), null);
-        //#snapshot-criteria
-      }
     }
   };