From 79a91220f6d95be715f0da48832ad34c9ada48c4 Mon Sep 17 00:00:00 2001
From: Janne Valkealahti <janne.valkealahti@gmail.com>
Date: Sat, 19 Mar 2016 09:09:19 +0000
Subject: [PATCH] Fix possible NPE

- Relates to #182
---
 .../persist/AbstractStateMachinePersister.java           | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/spring-statemachine-core/src/main/java/org/springframework/statemachine/persist/AbstractStateMachinePersister.java b/spring-statemachine-core/src/main/java/org/springframework/statemachine/persist/AbstractStateMachinePersister.java
index b7ef5f71..a9a6dd57 100644
--- a/spring-statemachine-core/src/main/java/org/springframework/statemachine/persist/AbstractStateMachinePersister.java
+++ b/spring-statemachine-core/src/main/java/org/springframework/statemachine/persist/AbstractStateMachinePersister.java
@@ -120,9 +120,12 @@ public abstract class AbstractStateMachinePersister<S, E, T> implements StateMac
 		for (State<S, E> ss : states) {
 			if (ss.isSubmachineState()) {
 				StateMachine<S, E> submachine = ((AbstractState<S, E>) ss).getSubmachine();
-				PseudoState<S, E> hh = ((AbstractStateMachine<S, E>) submachine).getHistoryState();
-				if (hh != null) {
-					historyStates.put(ss.getId(), ((HistoryPseudoState<S, E>)hh).getState().getId());
+				PseudoState<S, E> ps = ((AbstractStateMachine<S, E>) submachine).getHistoryState();
+				if (ps != null) {
+					State<S, E> pss = ((HistoryPseudoState<S, E>)ps).getState();
+					if (pss != null) {
+						historyStates.put(ss.getId(), pss.getId());
+					}
 				}
 			}
 		}