From c29d2b1be4be10c5069099ea47499398cf40fbc5 Mon Sep 17 00:00:00 2001
From: Dave Syer <dsyer@gopivotal.com>
Date: Mon, 4 Nov 2013 13:31:31 +0000
Subject: [PATCH] Remove a small race condition

---
 .../metrics/InMemoryMetricRepository.java     | 21 ++++++++++---------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/InMemoryMetricRepository.java b/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/InMemoryMetricRepository.java
index 8a62abc539..9c3d638e4b 100644
--- a/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/InMemoryMetricRepository.java
+++ b/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/InMemoryMetricRepository.java
@@ -35,22 +35,23 @@ public class InMemoryMetricRepository implements MetricRepository {
 
 	@Override
 	public void increment(String metricName, int amount, Date timestamp) {
-		Measurement current = this.metrics.get(metricName);
-		if (current != null) {
-			Object lock = this.locks.putIfAbsent(metricName, new Object());
-			if (lock == null) {
-				lock = this.locks.get(metricName);
-			}
-			synchronized (lock) {
-				current = this.metrics.get(metricName);
+		Object lock = this.locks.putIfAbsent(metricName, new Object());
+		if (lock == null) {
+			lock = this.locks.get(metricName);
+		}
+		synchronized (lock) {
+			Measurement current = this.metrics.get(metricName);
+			if (current != null) {
 				Metric metric = current.getMetric();
 				this.metrics.replace(metricName, current, new Measurement(timestamp,
 						metric.increment(amount)));
 				return;
 			}
+			else {
+				this.metrics.putIfAbsent(metricName, new Measurement(timestamp,
+						new Metric(metricName, amount)));
+			}
 		}
-		this.metrics.putIfAbsent(metricName, new Measurement(timestamp, new Metric(
-				metricName, amount)));
 	}
 
 	@Override