diff --git a/instrumentation/spring/spring-batch-3.0/javaagent/src/test/groovy/springbatch/TestItemWriter.groovy b/instrumentation/spring/spring-batch-3.0/javaagent/src/test/groovy/springbatch/TestItemWriter.groovy
index eb4fcf3349..be1cf78bdc 100644
--- a/instrumentation/spring/spring-batch-3.0/javaagent/src/test/groovy/springbatch/TestItemWriter.groovy
+++ b/instrumentation/spring/spring-batch-3.0/javaagent/src/test/groovy/springbatch/TestItemWriter.groovy
@@ -8,7 +8,7 @@ package springbatch
 import org.springframework.batch.item.ItemWriter
 
 class TestItemWriter implements ItemWriter<Integer> {
-  final List<Integer> items = new ArrayList()
+  final List<Integer> items = Collections.synchronizedList(new ArrayList())
 
   @Override
   void write(List<? extends Integer> items) throws Exception {