<Swing Dev> [12] RFR JDK-8204963:javax.swing.border.TitledBorder has a memory leak

[Krishna Addepalli]

Ah I missed that point. Yeah, inner classes (anonymous/named), when instantiated, will hold a strong reference to the outer class, so as long as this class is in memory, the outer class cannot also be garbage collected. 
The fix looks fine for me.

Thanks,
Krishna

-----Original Message-----
From: Prasanta Sadhukhan 
Sent: Monday, August 6, 2018 9:31 PM
To: Krishna Addepalli <krishna.addepalli at oracle.com>; swing-dev at openjdk.java.net
Subject: Re: <Swing Dev> [12] RFR JDK-8204963:javax.swing.border.TitledBorder has a memory leak

Hi Krishna,

Anonymous class or non-static inner class holds an implicit reference to its outer class. In this case, the anonymous class is a listener so as long the listener is registered, it holds a reference to the instance of the outer class. Making the listener static will allow the outer instance to be garbage collected. Unfortunately, I guess Java does not support static anonymous class so it needs to be a static named class.

Regards
Prasanta
On 8/6/2018 8:27 PM, Krishna Addepalli wrote:
> Hi Prasanta,
>
> Could you explain the fix a bit more. AFAIK, the earlier code should also not hold the reference to TitledBorder, longer than necessary.
> Whether an anonymous class, or a static named class, the UI manager would maintain a strong reference to PropertyChangeListener/TitledBorderPropertyChangeListener, which inturn maintains a WeakReference to TitledBorder.
>
> Thanks,
> Krishna
>
> -----Original Message-----
> From: Prasanta Sadhukhan
> Sent: Monday, August 6, 2018 8:11 PM
> To: swing-dev at openjdk.java.net
> Subject: <Swing Dev> [12] RFR 
> JDK-8204963:javax.swing.border.TitledBorder has a memory leak
>
> Hi All,
>
> Please review a memory leak issue in javax.swing.border.TitledBorder where it is seen that TitledBorder instances are never freed. This leak is an aftereffect of JDK-8152159.
> This is because
> javax.swing.border.TitledBorder.installPropertyChangeListeners() creates an instance of an anonymous inner class that implicitly holds a reference to the containing TitledBorder class.
> Proposed fix is to make it a named static class so that it does not hold reference and can be garbage collected.
>
> Bug:https://bugs.openjdk.java.net/browse/JDK-8204963
> webrev: http://cr.openjdk.java.net/~psadhukhan/8204963/webrev.0/
>
> 8152159 testcase also worked well.
>
> Regards
> Prasanta