<Swing Dev> How to resolve image tearing

[tom.hawtin at oracle.com]

On 27/05/2011 15:37, Walter Laan wrote:
>> We didn't change JComponent.repaint() to make it "no longer thread
> safe"
>> and I don't see why someone may think about it
>
> The bug report https://netbeans.org/bugzilla/show_bug.cgi?id=192548
> shows the stack:
> -
> With the latest changes to jdk7 and jdk6 update 22 it's no longer true
> due to
> repaint()'s call to getLocationOnScreen() which acquires AWT tree lock:

Whilst not ideal, it doesn't seem unreasonable that repaint should 
acquire a lock (that's usually how thread-safety is done).

The stack trace in that bug doesn't appear to show a deadlock as such. 
What it does show is Netbean waiting on one of its own locks on the AWT EDT.

"AWT-EventQueue-0" prio=6 tid=0x04713c00 nid=0x7d8 in Object.wait() 
[0x0599e000]

    java.lang.Thread.State: WAITING (on object monitor)
         at java.lang.Object.wait(Native Method)
         - waiting on <0x1c24efb0> (a 
org.netbeans.lib.editor.util.PriorityMutex)

Tom (not in AWT/Swing)