diff --git a/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/RunMojo.java b/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/RunMojo.java
index eb87989d22..48c165a915 100644
--- a/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/RunMojo.java
+++ b/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/RunMojo.java
@@ -85,7 +85,7 @@ public class RunMojo extends AbstractRunMojo {
 		while (hasNonDaemonThreads);
 	}
 
-	private static class RunProcessKiller implements Runnable {
+	private static final class RunProcessKiller implements Runnable {
 
 		private final RunProcess runProcess;