diff --git a/python/mozbuild/mozbuild/jar.py b/python/mozbuild/mozbuild/jar.py
index 0559a12c29d5..1bf279f711d0 100644
--- a/python/mozbuild/mozbuild/jar.py
+++ b/python/mozbuild/mozbuild/jar.py
@@ -517,7 +517,9 @@ class JarMaker(object):
 
         # copy or symlink if newer
 
-        if getModTime(realsrc) > outHelper.getDestModTime(e.output):
+        # if the output doesn't exist, we can skip an os.stat call
+        out_mod_time = outHelper.getDestModTime(e.output)
+        if out_mod_time == localtime(0) or getModTime(realsrc) > out_mod_time:
             if self.outputFormat == "symlink":
                 outHelper.symlink(realsrc, out)
                 return