Re: RFR(XS) 6625574: MemoryMXBean/Pending.java fails: "pending finalization = 0 but expected > 0"

[Mattias Tobiasson]

Staffan, could you please sponsor this fix?

Thanks,
Mattias

----- Original Message -----
From: staffan.lar...@oracle.com
To: mattias.tobias...@oracle.com
Cc: serviceability-dev@openjdk.java.net
Sent: Friday, February 28, 2014 1:58:44 PM GMT +01:00 Amsterdam / Berlin / Bern 
/ Rome / Stockholm / Vienna
Subject: Re: RFR(XS) 6625574: MemoryMXBean/Pending.java fails: "pending 
finalization = 0 but expected > 0"

Looks good!

Thanks,
/Staffan

On 28 feb 2014, at 13:56, Mattias Tobiasson <mattias.tobias...@oracle.com> 
wrote:

> Hi,
> Could you please review this fix?
> 
> The test often fails when run with command line "-Xcomp"
> 
> The test creates some objects and stores them in a local variable in the 
> function. The test expects those objects to survive until they are set to 
> null. The problem seems to be that the optimizer realizes that the objects 
> are never used and removes them before the test expects it.
> 
> The solution is to move the local variable out to a public static variable. 
> Then the optimizer will not remove it before expected. 
> 
> webrev:
> http://cr.openjdk.java.net/~mtobiass/6625574/webrev.00
> 
> bug:
> https://bugs.openjdk.java.net/browse/JDK-6625574
> 
> Mattias


# HG changeset patch
# User mtobiass
# Date 1393591131 -3600
# Node ID 511f475aa2c8dbad0f636851fc8c2a032f1d64db
# Parent  0731952efb104b783b75a5765a91a91601903a3c
6625574: java/lang/management/MemoryMXBean/Pending.java fails: "pending finalization = 0 but expected > 0"
Summary: Move local objs variable to a static public so the the optimizer will not remove it unexpectedly.

diff --git a/test/java/lang/management/MemoryMXBean/Pending.java b/test/java/lang/management/MemoryMXBean/Pending.java
--- a/test/java/lang/management/MemoryMXBean/Pending.java
+++ b/test/java/lang/management/MemoryMXBean/Pending.java
@@ -76,6 +76,9 @@
         System.out.println("Test passed.");
     }
 
+    // Keep objs public so the optimizer will not remove them too early.
+    public static Object[] objs = null;
+
     private static void test() throws Exception {
         // Clean the memory and remove all objects that are pending
         // finalization
@@ -105,7 +108,7 @@
         System.out.println("   Afer creating objects with no ref: " + snapshot);
         printFinalizerInstanceCount();
 
-        Object[] objs = new Object[REF_COUNT];
+        objs = new Object[REF_COUNT];
         for (int i = 0; i < REF_COUNT; i++) {
             objs[i] = new MyObject();
         }