diff --git a/src/main/org/apache/tools/ant/taskdefs/SignJar.java b/src/main/org/apache/tools/ant/taskdefs/SignJar.java
index 40038eb8a..67a4a37e0 100644
--- a/src/main/org/apache/tools/ant/taskdefs/SignJar.java
+++ b/src/main/org/apache/tools/ant/taskdefs/SignJar.java
@@ -435,7 +435,7 @@ public class SignJar extends AbstractJarSignerTask {
 
         // restore the lastModified attribute
         if (preserveLastModified) {
-            targetFile.setLastModified(lastModified);
+            FILE_UTILS.setFileLastModified(targetFile, lastModified);
         }
     }