<Swing Dev> [9] Review Request: 4339584 Adding a getUI public method to JComponent

[Alexander Scherbatiy]

On 8/21/2015 1:04 PM, Sergey Bylokhov wrote:
> Hello.
> Please review a small fix for jdk9.
>
> Long long time ago the next request was filed for jdk 1.4.0:
> "Today, there is no way for a program to access the UI of a 
> JComponent. Adding a getUI method would provide that capability and be 
> consistent with the fact that, for example, the JComponent's Border is 
> accessible"
>
> It was evaluated and was closed:
> "JComponent does not have a getUI so that each class can override it 
> to return the UI that is appropriate for the class, such as TreeUI or 
> TextUI..."
>
> The problem was in absent of covariant returns, which were added to 
> the jdk 1.5. So now we can add the "ComponentUI getUI()" method to the 
> JComponent and in the same time we will have an ability to override it 
> using more specific return value in subclasses.

   Could it break a binary compatibility if someone does not follow the 
javadoc specification and has in his program getUI() method which return 
type is not subclass of the ComponentUI?

   Thanks,
   Alexandr.

>
> Bug: https://bugs.openjdk.java.net/browse/JDK-4339584
> Webrev can be found at: 
> http://cr.openjdk.java.net/~serb/4339584/webrev.00
>