diff --git a/core/src/main/java/hudson/util/AtomicFileWriter.java b/core/src/main/java/hudson/util/AtomicFileWriter.java
index e18973caa9a0dcf26e2253c970f8045e3dee06fe..85db6338548cb7c7eb4692a9f8009ac09325226b 100644
--- a/core/src/main/java/hudson/util/AtomicFileWriter.java
+++ b/core/src/main/java/hudson/util/AtomicFileWriter.java
@@ -117,6 +117,7 @@ public class AtomicFileWriter extends Writer {
     @Override
     protected void finalize() throws Throwable {
         // one way or the other, temporary file should be deleted.
+        close();
         tmpFile.delete();
     }