diff --git a/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/MetricExportAutoConfiguration.java b/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/MetricExportAutoConfiguration.java
index b7d63aeb4d..8db866290b 100644
--- a/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/MetricExportAutoConfiguration.java
+++ b/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/MetricExportAutoConfiguration.java
@@ -71,7 +71,8 @@ public class MetricExportAutoConfiguration {
 
 		MetricReader reader = this.endpointReader;
 		if (reader == null && this.readers != null && !this.readers.isEmpty()) {
-			reader = new CompositeMetricReader(this.readers.toArray(new MetricReader[0]));
+			reader = new CompositeMetricReader(
+					this.readers.toArray(new MetricReader[this.readers.size()]));
 		}
 
 		if (reader != null) {