diff --git a/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/testkit/PluginClasspathGradleBuild.java b/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/testkit/PluginClasspathGradleBuild.java
index 80bf38a3a26..db29502da2f 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/testkit/PluginClasspathGradleBuild.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/testkit/PluginClasspathGradleBuild.java
@@ -95,6 +95,7 @@ public class PluginClasspathGradleBuild extends GradleBuild {
 			classpath.add(new File(pathOfJarContaining(KotlinCompilerPluginSupportPlugin.class)));
 			classpath.add(new File(pathOfJarContaining(LanguageSettings.class)));
 		}
+		classpath.add(new File(pathOfJarContaining("org.apache.commons.lang3.ArrayFill")));
 		classpath.add(new File(pathOfJarContaining("org.apache.commons.io.Charsets")));
 		classpath.add(new File(pathOfJarContaining(ArchiveEntry.class)));
 		classpath.add(new File(pathOfJarContaining(BuildRequest.class)));