diff --git a/compiler/compile_target_code.m b/compiler/compile_target_code.m
index c710fcf..ec87928 100644
--- a/compiler/compile_target_code.m
+++ b/compiler/compile_target_code.m
@@ -1708,15 +1708,19 @@ file_as_new_as(FileNameA, Rel, FileNameB, !IO) :-
 
 compare_file_timestamps(FileNameA, FileNameB, MaybeCompare, !IO) :-
     io.file_modification_time(FileNameA, TimeResultA, !IO),
-    io.file_modification_time(FileNameB, TimeResultB, !IO),
-    (
-        TimeResultA = ok(TimeA),
-        TimeResultB = ok(TimeB)
-    ->
-        compare(Compare, TimeA, TimeB),
-        MaybeCompare = yes(Compare)
-    ;
-        MaybeCompare = no
+    ( if FileNameA = FileNameB then
+        MaybeCompare = ( if TimeResultA = ok(_) then yes((=)) else no )
+    else
+        io.file_modification_time(FileNameB, TimeResultB, !IO),
+        ( if
+            TimeResultA = ok(TimeA),
+            TimeResultB = ok(TimeB)
+        then
+            compare(Compare, TimeA, TimeB),
+            MaybeCompare = yes(Compare)
+        else
+            MaybeCompare = no
+        )
     ).
 
 %-----------------------------------------------------------------------------%
@@ -3116,11 +3120,7 @@ create_java_exe_or_lib(Globals, ErrorStream, LinkTargetType, MainModuleName,
         io.remove_file(TempFileName, _, !IO),
 
         (
-            Succeeded0 = yes,
-            % Add an index, which is supposed to speed up class loading.
-            IndexCmd = string.append_list([Jar, " i ", JarFileName]),
-            invoke_system_command(Globals, ErrorStream, cmd_verbose_commands,
-                IndexCmd, _, !IO)
+            Succeeded0 = yes
         ;
             Succeeded0 = no,
             io.remove_file(JarFileName, _, !IO)