[OpenJDK 2D-Dev] [10] RFR: JDK-8188083- NPE in java.awt.image.FilteredImageSource.startProduction

Prahalad Kumar Narayanan prahalad.kumar.narayanan at oracle.com
Tue Nov 28 06:12:11 UTC 2017

Hello Sergey

Thank you for your time in review.
Yes..! As you rightly pointed, the test passes before the fix as well.

Reason is that, the occurrence of this bug is rare.
    . Submitter has observed only 15 occurrences of the exception with over 10,000 instances per month. 
    . Though the occurrence is rare, submitter is expecting a fix for this issue.

So what does this test-case resolve ?
    . Our change adds "synchronized" contract to the method to fix the Null pointer exception. 
    . To test the changes, we should check for both- Null Pointer Exception and any deadlock that could arise from "synchronized" contract. 
    . The test case helps to address both but in a passive way. Why do I say passive ?
          . First, the test provides a hope to detect & report NPE though its occurrence is rare.
          . Second, any deadlock arising from the concerned method, will cause the test to fail upon time-out.
Thank you once again for your time
Have a good day


-----Original Message-----
From: Sergey Bylokhov 
Sent: Monday, November 27, 2017 9:11 PM
To: Prahalad Kumar Narayanan; 2d-dev
Cc: Philip Race
Subject: Re: [OpenJDK 2D-Dev] [10] RFR: JDK-8188083- NPE in java.awt.image.FilteredImageSource.startProduction

On 24/11/2017 21:40, Prahalad Kumar Narayanan wrote:
> Based on discussions with Sergey, I 've now updated the fix with a test case.
> The changes are available for review under:
> http://cr.openjdk.java.net/~pnarayanan/8188083/webrev.01/

This version of the test is always passed before the fix(I have checked w/ and w/o jtreg).

Best regards, Sergey.

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