From 634020eea68d1f6664aae62e8eec8cfce75b2a74 Mon Sep 17 00:00:00 2001
From: Marcin Grzejszczak <marcin@grzejszczak.pl>
Date: Tue, 23 Aug 2016 15:34:44 +0200
Subject: [PATCH] Synchronizing on spans in ArrayListSpanAccumulator

without this change tests happen to have ConcurrentModificationException
---
 .../cloud/sleuth/util/ArrayListSpanAccumulator.java | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/util/ArrayListSpanAccumulator.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/util/ArrayListSpanAccumulator.java
index bfaeac69e..2a412d167 100644
--- a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/util/ArrayListSpanAccumulator.java
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/util/ArrayListSpanAccumulator.java
@@ -17,7 +17,6 @@
 package org.springframework.cloud.sleuth.util;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
 import org.springframework.cloud.sleuth.Span;
@@ -31,21 +30,25 @@ import org.springframework.cloud.sleuth.SpanReporter;
  * @since 1.0.0
  */
 public class ArrayListSpanAccumulator implements SpanReporter {
-	private final List<Span> spans = Collections.synchronizedList(new ArrayList<Span>());
+	private final List<Span> spans = new ArrayList<>();
 
 	public List<Span> getSpans() {
-		return this.spans;
+		synchronized (this.spans) {
+			return this.spans;
+		}
 	}
 
 	@Override
 	public String toString() {
 		return "ArrayListSpanAccumulator{" +
-				"spans=" + this.spans +
+				"spans=" + getSpans() +
 				'}';
 	}
 
 	@Override
 	public void report(Span span) {
-		this.spans.add(span);
+		synchronized (this.spans) {
+			this.spans.add(span);
+		}
 	}
 }